>>10
gaim[1] is the only one i know of.
i like kopete[2] better, but you can't use it on windows unless you use cygwin[3]...
>>11
it is the same version. i only have one version of gcc installed (3.4.4) and i compiled and installed a new version of firefox right before i compiled and installed scim the first time.
[1] http://gaim.sourceforge.net/
[2] http://kopete.kde.org/
[3] http://www.cygwin.com/