Pretty much what's on the tin. I absolutely do not have the bandwidth to run a GURPS game, but I'd love to play in one again. I figured I'd see if there's any interest or not.
For those that don't know, Infinite Worlds is a setting that Steve Jackson Games has developed and is the de facto setting for GURPS. It's based on what I think is called the Multiverse Theory of the universe, basically there's multiple timelines that have diverged from a common point and you can travel up and down those timelines by visiting echos. The setting book focuses on the police force that goes flitting about looking for troublemakers, rescuing teams that get into trouble, and looking for agents. There's more to it than that, but I haven't looked at the book in a while so I'm going off what I can remember.
Basically, you're playing interdimensional, time-travelling cops and peace keepers that are also trying to gather intelligence and get new technologies to help advance the prime civilization where/when this group is headquartered.
GURPS Page on SJGames.com
Infinite Worlds Book page on SJGames.com
Infinite Worlds Page on the GURPS Wiki