SLEDcc2008 (the convention) will take place in Tampa, FL on September 5-7 this year. If you can’t make the real life event, there will be a corresponding conference taking place in Second Life–for free. So there’s no excuse not to be there in some fashion.
There is also plenty of time to volunteer, especially for the in-world activities. There is a long list of interesting in-world volunteer positions. I still don’t know what SLED Sparks are, but it all sounds very interesting. This is also your chance to find out first hand what educators are doing in SL so that you can communicate better to your administrators.