Wireless PDA - just how wireless are they?

[GreenBug]

Been reading up wireless technologies and got interested in wireless PDA's. In particular the Palm i705 has caught my eye.
I have read up on Specs for the i705 as well as Cingular, the company who carries the wireless signal for this device, trying to get an idea on the product and how it functions.

Ive worked with Blackberry and palm V - but those devices were hotsync'd at the workstation. Wireless PDA's are new to me.

Just how wireless is the new age of PDA's? Can i be downtown or at home and check business email? - or - will I still have to be within 10-15 feet of an access point?

The idea of being completly wireless is just too cool, but I want to make sure that I understand the range and capablitly of this device before I sink 500$ into it.