Kally - try this and let us know:

go to Settings - Application manager

select the menu and Tools - Application catalog

select maemo Extras in the list and press the Edit button

make sure that the Disabled checkbox is not checked

press OK and Close

Refresh the list

press Browse installable applications

scroll down to the instantmessaging button

From here you can install the Pidgin Internet Messenger

you might also want Pidgin Sounds and the Default Smiley Theme