I will try to get more specifics, but the basics for me are:
Remote Desktop (symbol is RDP)
Mocha Remote Desktop
Version 2.2
mochasoft.dk/iphone_rdp.htm
this will provide access to a PC running Windows XP, Vista or 7 (but not the home version). NOW IT SAYS THERE IS NO SUPPORT FOR WINDOWS SERVERS, but I log onto my account on the server and it runs as a remote desktop. I suppose there is a host of server functions that I can't run, but guess what? I don't know how to run them anyway.
You do have to buy the commercial version, (I think the app was like, $20) in order to have the most encryption. It is a one time fee. It loads REALLY fast, and gets me into Amazing Charts fast enough that 2 or 3 times a day I load it, then hand it to a patient and turn my lap top around so that they can see both screens, which match. For the technically savvy patients who have just announced how impressed they are with out practice using an EMR, I then hand them the phone and brag, "I can open your chart, and fax your last EKG or your medication list, to the Emergency room physician, while I am sitting in a restaurant, anywhere in the country." It's not much of an exaggeration, but it is a stunning thought.
In my experience the phone is so small that negotiating the keyboard to chart a visit would be possible but completely impractical. But to open a patient chart and review meds, or to fax a note, or the EKG to myself at the hospital is VERY easy and very useful.
The iPhone combined with the access to amazing charts, and I have the app's for the CDC, Quest Labs, Epocrates (which I use A LOT) and an ICD-9 and Differential Dx APP. This group makes it VERY useful.
