GTalk packet analyzer

[southsys@gmail.com]

I used tcpdump to examin some gtalk packets on my linux fc6 box. It looks like gtalk uses compression before sending/receiving data. Here is a sample of what I see when looking at the packets with wireshark...

Accept-Encoding: gzip, deflate

The above text looks like it might be part of a long URL directed to mail.google.com. A text string follows something like "GX=......." and I am wondering is this is just the compressed message part of packet.
Are there any freeware programs capable of reading a tcpdump raw file and decoding the gtalk packets?