9to5Mac's source says that four new MacBook Air models will be released. Two 11 inch models and two 13 inch models. The main updates will be Sandy Bridge processors and Thunderbolt I/O.
The new Mac Pro is rumored to have a redesigned enclosure that is narrower and rack mountable. Obvious additions are Sandy Bridge and Thunderbolt. A Mac Pro Server model is also said to debut.
It's thought that Apple may release Mac OS X Lion and its new MacBook Air and Mac Pro on Thursday.