The ZMan:Your best bet is to post in your playtest /review thread a list of times you will be online, or an IM/email contact so that people can ping you. Most important - make sure its a game that people want to play and make sure you have been a good Indie Citizen and are doing playtests yourself.
The SystemLink is working fine, even with latency simulation. The xbox live is not tested, because i cant test it alone, but is the same code than sistemLink but with a different type of session. I will ask for help in the playtest game forum. Thnx for the suggestion.