some people have trouble connecting to Gtalk on Kopete here is hoe to do it.
Open Kopete go to Settings>>configure>>accounts
Add a new Jabber account.
Enter your complete Google Mail address and corresponding password.
go to the Connection page of the dialog.
check “Use protocol encryption (SSL)” checkbox
check “Allow plain-text password authentication” checkbox
check “override default server information” checkbox
and set server to “talk.google.com port 5223
If you are behind a firewall and can’t connect to the 5223 port you can use the 443 port (standard SSL port).

there you are all set to connect and enjoy
NOTE :- if you recive some sort of SSL errors just install the qca-tls package by ‘sudo apt-get install qca-tls’ in debian/Ubuntu