the ipod touch is similar to the iphone i was able to hack it when i had it and install custom applications on it. Very similar to the iphone the difference being it just isn't a phone lol! In general it would do most things an iphone would do.
Of late i haven't kept upto date with the latest developments of it, so unsure what is going on now!
yeah Apple have done a clever thing designing the new iPhone to support business features like Cisco VPN's and Microsoft ActiveSync (push email etc). Quite a few companies I know are now considering getting them for field-based employees.
Still a few technical & security concerns - particularly regarding centrally applying policies to the phones to stop users them filling their work iPhones up with dodgy films and music... But for their price, new iPhone could now really be a serious player in the Windows Mobile/PDA/Blackberry corporate-user market.