According to Government Computer News, the US military forces in Iraq are using ruggedized handhelds and portable PCs to help with battle information:

Troops on the ground in Iraq are using ruggedized portable PCs and personal digital assistants to support operational and logistical applications.

Equipped with a Global Positioning System receiver and a tactical military modem, and coupled with a laser range finder, PCs and PDAs can be used to transmit firing coordinates to artillery on the ground or to aircraft overhead. They supply maps and personnel information for medical evacuations and carry maintenance manuals for military vehicles.

...via Gizmodo