well, that messenger is miranda.get it for free at
http://miranda-im.org
tha windowsstyle you can not see is applied with tuneup utilites. (can be done with stylexp, too)
that calendar is rainlendar, that winamp thingy on the left is rainmeter.
and the stuff on the top is objectdock.
the last 3 programs are all free, too. just google for them
if you have got further questions you may contact me of course