Panda Egg is a graphic (non-ASCII) Go client for IGS. With it, you can play on and connect to IGS, as well as replay your games, if saved through the Egg in UGF format.
BobMcGuigan: Panda Egg has another use in addition to being an IGS client. It also serves as a viewer for the "live" presentations of title match games (and others) on Japanese newspaper go column web pages. See Japanese Go Column URLs and UGF Format.
IGS provides the program without cost, but it only runs on Windows. Source code is not available.
See http://www.pandanet.co.jp/English/setup/index.htm last ver: 8.40a (aug.'06 and still march'09)
Panda-Egg annoyingly saves its games as UGF files instead of SGF files. Converting these files to sgf is possible with e.g. glGo, Multigo, GoKnot  (but graphics in the ugf-files cannot be extracted in this way). The Linux utility ugi2sgf converts and also saves the graphics.
Convert on-line at: http://www.ask.ne.jp/~sakana/Go/ugf2sgf_e.html.  dmikur
Easiest is to not use the client to save the game record files. Instead set the IGS function 'automail' on and IGS will mail you all your game files in sgf format. The command to turn on automail is 'toggle automail' (Egg has a command line? - but glGo has!). The return will tell you whether you have toggled automail on or off (presumably on but if not, just toggle it again). If you want to have games that you watch mailed to you then you need to study the syntax of the 'mail me' command (on IGS type 'help mail' and the help file will explain. DaveSigaty
I noticed that in the English version of the software, the list of points doesn't show up for me in the 8.00d and the 8.01 versions. This is a bug, but I don't know how to send the message to the Panda Egg developpers.
choreck: Anyone knows meaning of Panda, apart from the Panda bear we know? So that, this is used along with IGS?
 You can convert UGF to SGF using GoKnot. GoKnot is available at http://www.dybot.com/GoKnot and it opens both SGF and UGF. If you use Panda Egg, in Windows I presume, you could consider using GoKnot for much more than just converting files. Jacques.
 Minor note about the UGF-to-SGF online-converter above: for me, for the games I've tried it with, it doesn't add the closing parenthesis character ')'. That caused a problem with the program I use (JagoClient), but manually editing the file and adding the closing parenthesis solved it. Cornelius (3/'09: still the same)