Just a quicky, to get identi.ca working with pidgin:
1. Enter your gmail address in identi.ca
2. In pidgin add firstname.lastname@example.org as a buddy
3. You will get an authorise request (or 4 🙂 ) just authorise the first one and give it a sane name like Identi.ca
4. Try sending it an IM, this will probably fail with a message :
Identi.ca: [Identi.ca] Unknown user; go to http://identi.ca/settings/im to add your address to your account
5. Look at what username your message went from in my case it was email@example.com/Home
6. Pop back into the Identi.ca web page for IM settings and change your IM name to what ever it sent it as
7. You will get a message from Identi.ca saying basically click on this link to confirm your jabber id.
8. Click on it.