The best way to install gaim for Mandrake is to either:
1) Go to the command line, su to root, and type "urpmi gaim"
2) Open the Mandrake Control Center, go to the SOftware manager --> Install Software screen, search for "gaim", select the package and click "Install".
Both of these methods do the same thing: they use the 'urpmi' system to fetch the package and any dependencies
and install them. By default, they will take the packages from your installation CDs. For more options, set up your urpmi mirrors with the command line. See my sig for a link to EasyUrpmi.