you can use Pidgin Internet Messenger which supports both of them (if im not wrong) Perhaps you need to enable extras-testing and extras-devel categories.
Thanks RiD please suggest how I get to the download page? normal google search?
first you need to enable extras devel catalog, http://nokia-n900.com/forum/nokia-n900-maemo-apps/get-access-to-more-maemo-application-catalogs-108/
may help you.
after you add, go to the application manager and search for pidgin. it should find only one result. install it. then just open the application and set up the accounts. it supports a lot of services
also, when installing other applications from extras devel make sure you really want to install. extras devel applications can be unfinished / bugged or not optified. but pidgin is good
when you select an application to install you can see which catalog the app is placed.