So here’s how I configured Pidgin to work with a nonprofit Google Apps account. OS is Ubuntu.
1. Select “Add/Edit” from the Accounts menu, then press the “Add” button.
2. Fill in fields on the basic tab.
* Protocol: XMPP (Do’t use gmail option)
* Screen name: sharadaprasad
* Domain/Server: yourdomainname
* Resource: Home (or Anything)
* Password: ********
* Local alias: CSP (Can also be Blank)
3. Fill in fields on the advanced tab.
* Check – Force old (port 5223) SSL
* Change Connect port to 5223
* Connect server: talk.google.com
* Proxy type: Use GNOME Proxy Settings
Leave the rest untouched.