The major player gathering for EVE Online players is Fanfest, which is held in Reykjavik each year. However, the fact is many players can't make the trip to Iceland, and a number of North American players have hoped for an event that's more accessible to them. It looks like this is going to happen, and what's more accessible than Las Vegas? (Bonus: "What happens in Vegas, stays in Vegas.")
The 2009 EVE Developers Meet and Greet in Las Vegas was mentioned very briefly during the recent (and excellent) Alliance PvP Tournament, but more info is available now. EVE Vegas is a two-day event that will be held on May 8th and 9th at the Imperial Palace (on the Strip). It kicks off on a Friday with the Meet and Greet, followed up by a conference on Saturday.