I believe there is an addon for WOWRoster called Event Calendar that allows you to integrate GEM into your Roster site. Haven't used it so I can't say how good it is but if it is half as good as Roster then it is well worth a look (and no, I dont work for them!)
Massively's Free Realms beta key giveaway
Apr 17th 2009 9:33AM (Massively)Organizing raids with Raidar
Oct 21st 2006 5:18AM (WoW)Roster: http://www.wowroster.net/
Event Calendar: http://www.wowroster.net/Forums/viewforum/f=59.html
Gob - Nordrassil EU