Many of the big gaming websites are beginning to publish their previews of GTA IV PC's multiplayer functionality. The aforementioned functionality is practically the same as the console versions, but with player limits increased to 32, and the addition of a much sought after server browser. The websites recently got to play multiplayer matches against Rockstar employees from their various studios, unfortunately they never got to test out the server browser since R* were setting up all the matches for them. Sites that currently have their previews up are:
Nothing new in any of them really, but you may like to read them, especially if you don't own a console version and haven't actually played multiplayer GTA IV yet.
1UP also added 8 brand new screenshots of GTA IV PC. You can check them out in the linked gallery.