A quick search on Google pdfs on iPhone threw up some interesting links.
There's a link here from David Pogue about reading books on the iPhone:
http://www.oreillynet.com/mmgadgets/..._iphone_1.html
Seems to be that there's an inbuilt pdf reader that is used by Safari as well.
I found a lot of interesting material about pdfs in iTunes (of all things) it looks like you can download pfs in the same way as you download a track - or subscribe to one in the same way as you subscribe to a podcast. Presumably you can then get them onto your iPod touch simply by syncing.
I'd love to see FeedBooks on there!
Here's the
Complete guide to pdfs on ITunes. If you're curious you can also try searching for '.pdf' ino the itunes store search ending.
Of course good old basic html is still very much an option as well.
The dilemma for me is whether to get one now or wait for the HD version. the lack of the HD version is a bit of a disappointment. I'm sure Apple will produce one - there would be a hell of a market among photographers especially if they build in RAW support.