Good Overview on Demolition of the WTCfrom the "Demopedia".
This section discussing how bombs might have been planted in the WTC is especially good.
The article is a good overview on 9/11 in general. I don't know how long it will last in it's current form, though, given the format of the Demopedia and DU's attitude to 9/11.
In terms of demolition, the big question the official story simply can't address is: how did the central cores of the towers collapse so easily?