There is a social group for resident and visiting gay expatriates and friends in Buenos Aires that meets on the first and third Thursday of every month. The group is called Gays Away in Buenos Aires and details of the next meeting can be found here -
http://groups.msn.com/GaysAwayinBuenosAires/

Gay tourism has really taken off this year (2006) with visits by more gay cruise ships and the start of construction of a gay 5-star hotel. There is a new web-site called Guide to Gay Buenos Aires which has loads of information about hotels, discos, bars, saunas, cruising and much more. Find it at http://buenosaires.queercity.info/