I just got a 770 for Christmas. The first thing I wanted to do was put AIM onto it. I was about ready to eat my nokia 770 because I couldnt figure anything out after hours of reading guides. Well I finally I figured it out and I hope this can help you too.

From one noob to another's guide:

(1) Follow the directions closely.

(2) Make sure your Nokia 770 is connected to the internet.

(3) On the left menu bar click the double window looking button,
then go to Tools -> Application Manager

(4) On the top left corner of the application manager is an
upside-down ^ symbol. Click that and go to
Tools -> Application Catalog...

(5) On the catalog list click the New button.

(6) In the new window that pops up, type the following information:

Web address: http://repository.maemo.org
Distribution: mistral
Components: non-free
Enabled box checked

(7) Click the OK button. It will ask you if you want to refresh, click OK

NOTE! If you get a message saying that it was unable to refresh the list, then you are doing something wrong. A lot of people try to add the other catalog list FIRST and you will get this error.

(8) A successful refresh will bring you back to Application manager.

(9) Now enter a new catalog list by following steps 4 & 5 again, but this
time type the following information:

Web address: http://maemo-hackers.org/apt
Distribution: mistral
Components: main
Enabled box checked

(10) Refresh to verify it installed OK (meaning no unable to refresh msg)

(11) Near the top left of the application manager is the word "Main"
written. Click that to go to the main menu.

(12) From this window, click "Install new applications"

(13) Under Applications, you shoud find Gaim. (If not just click the
All button and find it). Once you find it click install.

(14) After a successful install, you still need to install the protocol.
In the App. Manager under Main->Install New applications
click the Protocols button.

(15) Here select the client that you use. I use AIM, but I assume
the others work too.

(16) Upon succesful instal Click on your programs button and go to
Extras.

(17) Run Gaim Instant Messenger, enter your account info and VOLIA!

Now, if you can get the meanwhile protocol working, post that for this noob.