KXOK

St. Louis, Missouri's KXOK was an Urban Adult Contemporary station beginning in 1992 and later played Classic Rock circa 1999/2000.  97.1 FM is currently KFTK and carries a Talk format.

WRHU

88.7 FM WRHU broadcasts from Hofstra University in Hempstead, New York.  The student-run outlet was named the best college radio station in the country as ranked by the The Princeton Review.  WRHU is the flagship station of the New York Islanders, the first and only college station to have an exclusive broadcasting agreement with a professional sports team.

WHO

A t-shirt featuring the long-time owl mascot of News/Talk 1040 AM WHO in Des Moines, Iowa.  They are a 50,000-watt clear channel station and went on the air in 1924.  A look at recent Nielsen Audio ratings for Des Moines shows they were ranked #1 in the market.

President Ronald Reagan worked at WHO from 1932 to 1937.

WUSC

90.5 WUSC is the student-run radio station of the (W) University of South Carolina in Columbia.

Radio Quattro

Radio Quattro broadcast in Florence, Italy.  Not sure if they still exist or are related to this station.

KTBQ

"Q107" KTBQ plays Classic Rock in Nacogdoches, Texas.

CIAM-AM

A 1987 sticker from CIAM, a Top-40 station in Cambridge, Ontario.  Ten years later, approval was given to move to 92.9 FM and broadcasting on 960 AM officially ended in August, 1998. 

CIAM-FM

CIAM is a Religious station licensed to Fort Vermilion, Alberta.  They signed on the air in 2003 and are heard on more than a dozen rebroadcasters in three provinces.

BBC Radio Foyle

BBC Radio Foyle broadcasts from County Londonderry, Northern Ireland.  They've been on the air since 1979 and are named after the River Foyle which forms the border between the Republic of Ireland and Northern Ireland.

KMKF

KMKF is a Rock station in Manhattan, Kansas.

WSHZ / Mystery Z108

A 1998 sticker from Hot Adult Contemporary "Z108" WSHZ in Muskegon, Michigan.  107.9 FM is currently WMUS and has a Country format.

I don't know if this t-shirt is from WSHZ or not...do you? 
UPDATE:  This shirt is from WPEZ in Macon, Georgia.  Thanks Vaughn!

KFZX

A 2002 sticker from KFZX licensed to Gardendale, Texas.  At that time FZX played a mix of classic, alternative and current songs under their "Absolute Rock" branding.  They currently carry a Classic Rock format.

WXTQ

WXTQ was a Rock station in Athens, Ohio.  They now carry a Hot AC format known as "Power 105."

WKGR

WKGR "98.7 The Gater" is a 100,000-watt Classic Rock station in West Palm Beach, Florida.

WOUB

91.3 WOUB is the flagship of the five-station Ohio University Public Radio Network based in Athens, OH.
In the mid-1980s WOUB had a Classic Country show on during drive time complete with jingles and listener requests. 

A WOUB license plate frame.

KLCX

The front and back of a t-shirt from KLCX in Eugene, Oregon.  They were on the air from 1987 to 1993 before flipping to CHR as KDUK.  KLCX was licensed to Florence, OR.  Anyone know what Worden & Goodman's "Lic Me!" was all about (and why it was spelled like that?)

UPDATE:  See comments.

WACR

A vintage shirt from WACR (W Allentown College Radio) in Allentown, Pennsylvania.  WACR apparently still broadcasts (a student handbook from 2013-2014  lists them in the campus directory) but there doesn't seem to be any online presence for the station.  Allentown College changed names in 2001 to DeSales University which also has an internet-only station WDSR.  The WDSR Facebook page says that WACR began broadcasting in 1975.

KMPS

Seattle, Washington's KMPS plays Kountry Music for Puget Sound.  They've carried the same format since 1978.

KARM

KARM began broadcasting in 1938 at 1310 AM in Fresno, California.  This oversized, mid-1970s(?) "Sam Schwan for President" sticker dates to when the Broadcasting Yearbook says they carried a News format.  1430 AM is currently an Oldies outlet KYNO.

WLRS

WLRS signed on the air in 1964, originally as a training ground for students at the (W) Louisville Radio School in Louisville, Kentucky.  The station was at its peak in the 1970s as an Album Oriented Rock station and topped the city's Arbitron ratings in 1978.  In 1991 they flipped to Adult Contemporary as "Mix 102" and about six years later switched to Alternative Rock.  WLRS later moved up the dial to 105.1 FM, while 102.3 became WULV with a Soft AC format.  102.3 FM is currently Hot AC "The Max" WXMA.  Airchecks, photos and other memorabilia from the glory days of "The Walrus" can be found here.

WGAR

WGAR has been a Country station in Cleveland, Ohio since 1984.  The call letters stand for (W) George A Richards, a man of questionable ethics who owned KMPC in Los Angeles and WJR in Detroit as well as the Detroit Lions football team. 

WBRM

1250 AM WBRM plays Country music and is licensed to Marion, North Carolina, at the edge of the Blue Ridge Mountains.

WPTS

92.1 WPTS is a 17-watt, student-run station at the University of Pittsburgh in Pittsburgh, Pennsylvania.  The transmitter is located on top of the Cathedral of Learning, the tallest educational building in the western hemisphere and centerpiece of the university's campus.
Radio at Pitt began in the late 1950s when a group of students formed the Student Broadcasting Association with the intent of getting a station on the air.  Led by Adrian Cronauer (whose wartime experiences became the basis for the 1987 movie Good Morning Vietnam) they finally succeeded in 1961 broadcasting at 820 AM with call letters WPGH.  The struggle to find room on the FM dial ended in 1984 when the FCC granted them the last ever 10-watt Class D license to a station on the commercial band.

Radio Mare

Radio Mare ("Radio Sea") broadcast in La Spezia, Italy from 1988 until 1998.  About seven years later Radio Mare returned as an online station.

KCLB

Yesterday I posted a bunch of stickers from KRXQ "93 Rock" in Sacramento, California.  The above decal was filed in with them but it's pretty clear that this sticker isn't from KRXQ.  It's probably from 93.7 KCLB which was known as "The Rock" from 1991 until 2005.  KCLB is licensed to Coachella, CA...nowhere near Sacramento.