Hey Tom. Blackberries are very user friendly, in fact, most usually become rather addicted to them, giving them the nickname Crackberry.
The new ones have some nice features. They are also cell phones and mini web browsers [surfing isn't great, by any stretch, but it's there.]
I just bought about 150 Blackberries. The attorneys were invited to pick between a handheld and a desktop, or a laptop. There were only about 20 laptops chosen, 30 PocketPCs and maybe 15 Palms. [And we only showed the monochrome blackberries in the review.]
We evaluated several carriers for them [if you get a BES, it is carrier-neutral] and settled on T-Mobile. I would have liked to evaluate Nextel's choice, but they were banned by someone in our telecom section for some reason. AT&T was the only other real alternative at the time, and they had fewer towers [they rent from a lot of T-Mobile towers, it turns out] so I had my mind made for me, to a large degree.
The BES give s you much more responsiveness than simply forwarding a copy of the email to an internet account. It isn't all that expensive, considering, but be careful on the CALs. Shop around for a good deal. If you can't afford their support [also not unreasonably expensive] you may be able to just call your carrier and have them escalate the issue to RIM themselves. We did that for the duration of our trials.
There are many other little features with the Blackberry and a BES that may interest you. Not only can the users surf the web, they can surf your intranet. This could be exceptionally appealing to your employers, depending on what it is they need to see...
I strongly recommend that you have a blackberry and use it a little while before giving it to them, though. There is little support in the community - most people just buy RIM's packages.
If you're not comfortable with Blackberries, you can also accomplish this with newer models of PocketPCs and Palms/Treos. Visit www.extendedsystems.com and look at their XTND Connector [now called One Bridge Connector, I think].