you need to download and install gtkspell first, it isn't part of the slackware distro.
i believe there's a package on linuxpackages.net, or google for the homepage and compile it yourself.
then jsut run the gaim.SlackBuild script from the slackware mirror
ftp://ftp.slackware.com/pub/slackwar...ource/xap/gaim
as a guess (URL is from memory)
-0-