The new release of Messenger Plus! for Windows Live Messenger now allows for in-memory skinning! It’s a great feature which should see some very interesting skins being released over the new few months!
MPSkins.net doesn’t currently contain much except for the skinning documentation at the moment, but I hope to add more content soon.
I have also recently created the Messenger Plus! Stuff Network (not to be confused with Messenger Stuff), which at the moment is just a placeholder page, but in the future I hope to have it at the centre of the network of sites with some interesting features such as a single login system across the sites and merged profiles, listing a users SoundPacks, Scripts and Skins on one page!