^OH! so u are telling windows transperancy
well yaar,ur looking for window border themes.which u can get a lot(heard Linsta?
) from
http://gnome-look.org .try for metacity(window border) and gtk2 themes there.search ubuntu forums for more customization.try @shashwath panth's guide for a mac look if u want
The Ultimate Ubuntu Customization Guide!
and to install themes,u can go to menu System>preferences>themes.
u can install many gtk2 theme engines from synaptic package manager(in menu system>admin>synaptic)
edit:I'll tell u-dont try compiz-fusion at this time.it is still very beta.beryl project was merged back to compiz to form compiz-fusion.u can see some screenshots of mine in post linux screenshots thread.
http://www.thinkdigit.com/forum/show...&postcount=289