ok what you need to do is search the pages here at LQ, lots of info.
there should be a script called build_icon.sh in your /usr/share/engage/ folder
copy that to ~/.e/apps/engage/ and then go to deviantart.com and download some nice looking icons.
then run the following lines to creat the icon on engage. this one will create an icon for Gaim using the icon i told it to. the way to do it is : make sure you type in everything after the $
jhawk@razorback engage $ sh build_icon.sh
Usage: build_icon.sh app_name app_exe window_class window_name icon_name
in order to get the window class, which is very important run :
jhawk@razorback engage $ xprop WM_CLASS|cut -d \, -f 2
then just put that where it needs to be hit enter and you have your icons!
below is an example using an excellent iconset from weboso check out his stuff at DA.com
jhawk@razorback engage $ sh build_icon.sh gaim /usr/bin/gaim Gaim gaim ~/.icons/aim_2004_02.png