Studio Daily notes a review of the Elgato Turbo.264 USB thumb drive encoder at Ken Stone's website. It looks pretty cool for $99 and should be even more handy when Adobe Media Player is finalized.
The best overviews on AMP and h.264 still seems to be Flash engineer Tinic Uro's What just happened to video on the web? and New File Extensions and MIME Types.
"the moov atom (which is the index information in MPEG-4 files) is at the beginning of the file....you have to wait until the file is completely downloaded before it is played back. You can use tools like qt-faststart.c written by our own Mike Melanson to fix your files so that the index is at the beginning of the file."