Here’s Apple’s documentation for developing web stuff for the iPhone. It’s not all that surprising mostly, but it is good to keep a link to this hanging around.

Apple Developer Connection – Web Development for iPhone

Addendum: Josh, if you are looking for info on which codecs, bitrate etc to use for the iPhone, here it is: on a subpage of the above link.. Basically:

The Movie to MPEG-4 exporter with the following settings prepares movies for Wi-Fi.
In the H.264 video options, make sure you restrict the encoder to use the Baseline profile, and select “Faster encode (Single-pass)” encoding in the Video Options dialog.
Video settings: 900 kbit/sec, H.264, 480 x 360; frame rate: current; preserve aspect ratio using: Fit within size
Audio settings: 128 kbit, AAC-LC
.mp4 file
The Movie to 3G exporter with the following settings prepares movies for EDGE.
Video settings: 64 kbit, H.264, 176 x 144; frame rate: 10 or 15; preserve aspect ratio using: Letterbox or Crop
Audio settings: 16 kbit, AAC-LC
.3gp file

Addendum: I’ve had no luck getting my video-conversion Swiss Army knife, ffmpeg to generate H264 video. Normal MP4 video with the WiFi bitrate settings works fine. I had some difficulty with making 3gp files, but MP4 files at the lower bitrates work well too. I’ll post links to some examples after I’ve tweaked them a bit more.