It only saves the last 20 lines of chat (and only if the window was closed properly, otherwise it will NOT save the log).
Since Google Talk currently lack any normal API (heck, its just one executable file ;-) ), I thought about writing a small up that would listen to file changes in the log directory, parse them and accumelate them in one file per converstaion with a person (similar to what the log is doing now).
This will allow me to save the complete log of the chat.
I was also fiddling around with making my small app, a Google SideBar add-on. All I can say is that its not that nice to make one :-).
Actually, I didn’t have enough time (I think a hour should do it) to mess around with it too much.
Anyhow, I’ll update all of you on how my Google Talk mods are coming along.