Here is how you do it:
1. Sign in to your favorite Google Talk
2. Add an ID service@gtalk2voip.com to your Google Talk
3. Add another ID 106@radio.gtalk2voip.com (The number before the @ sign stands for the FM station ID)
4. Now make a call to 106@radio.gtalk2voip.com to enjoy some great music.

Here are list of FM radio stations you can enjoy via Google Talk:

100 – 181.fm – Kickin’ Country (Todays Best Country!), http://scfire-chi0l-1.stream.aol.com:80/stream/1075
101 – 1.FM – Country, http://64.62.194.11:8020/
102 – Atlantic Sound Factory – ASF Radio, http://69.31.50.146:80/
103 – 100.7 Jack FM, San Diego, http://38.116.132.31:9024/
104 – 102.7 FM The Fringe, http://64.72.124.89:8134/
105 – 181.fm – The Buzz (Your Alternative Station!), http://scfire-nyk0l-1.stream.aol.com:80/stream/1022
106 - 181.fm – The Mix Channel (70s, 80s, 90s and Today’s Best Music) , http://208.53.158.167:8032/
107 – 181.fm – The Eagle (Your Home For REAL Classic Rock!), http://208.53.158.126:8030/
108 – .977 The 80s Channel, http://scfire-ntc0l-2.stream.aol.com:80/stream/1040
109 – 1.FM – Channel X, http://209.51.161.54:8072/
110- Teen Taal Radio (HINDI), http://213.251.129.40:8022/
111 – Radio Helsinki – 92.6 MHz, http://88.198.49.11:8000/live56.ogg
201 – KCRW World News, http://scfire-ntc0l-2.stream.aol.com:80/stream/1047
202 – Sporting News Radio, http://scfire-chi0l-2.stream.aol.com:80/stream/1057
203 – KPFK – Southern California’s 90.7 FM News, Talk & Music, http://64.27.31.66:80/
204 – WBUR 90.9 FM, Boston’s NPR News Station, http://205.234.188.21:80/

[source tothepc]