"The Army intends to increase the number of Active Component brigades from 33 to 43 by fiscal year 2007; at that time, the Army will decide whether to continue the process to achieve 48 brigades. During the same time period, Army National Guard Brigades will reorganize into 34 brigade-size units using the same modular design as the Active Component." from

"Where are the Legions? [SPQR] Global Deployments of US Forces"
http://www.globalsecurity.org/military/ops...deployments.htm

So ten new brigades are coming online by 2007.

This may only be for Iraq or for the entire region, see Christian Science Monitor article http://www.csmonitor.com/2002/0319/p01s04-wosc.html
and click onto 'see map' for deployments.