As of this writing I am now about 6 weeks into my iPhone 3G and using it as my primary phone as well as email and web device.  I have to say having been a TREO fan for many years, I am now a solid iPhone guy.

As Prudential's top Realtor in the Portland, Oregon area and as a technology speaker travelling around the USA and Canada speaking to Realtor groups, I rely heavily on my phone as well, a phone  AND as an email device.  Using Microsoft exchange server I am able to see my emails in full HTML.  But the best part is the way PDF files are shown - its like looking at them right on my computer, I can even turn the phone sideways and see the file horizontally.  I just now reviewed a 47 page home inspection in full living colour, and then forwarded it on to the listing agent to review, all while taking a day off on the Oregon coast.  I get my faxes as PDF files and many agents now send documents via emailing PDF files so I truly dont need to drag along my laptop computer anymore.

Other features of the phone include applications such as Trulia's home search program where it uses the GPS function of the phone to locate itself and then show all the homes for sale around you.   There are also several mortgage calulators and more to dowload, and of course the Safari browser is a full-fledged internet browser.

For Realtors, or for anyone I can very strongly reccomend the iPhone 3g from Apple.