You can try the following solution I found on the PPRO wiki, but I think you'll need Quicktime (QT) PRO to do a "Save As". I have QT Pro installed, so this method works for me.
If you try to import an MPEG-4 file into Premiere Pro 2.0 you’ll get a big fat dirty error message stating File Import Failure with a terse reason, “File format not supported”. Well, that’s not entirely true if you can play the file back through QuickTime 7. Simply open the file in QT 7 and go File -> Save As… -> Save as self-contained movie and it will now work!
Note that you cannot simply rename the .mp4 extension to .mov and expect it to work. What happens is the file’s header is rewritten to contain it within QuickTime’s API and allows Premiere Pro 2.0 to access the file without recompression. Hooray!
If turns out that you need QT Pro and decide to drop $30 then I would highly recommend
getting the AVS converter
I picked this converter up earlier this year and have been very happy with it. It supports a ton of formats and it easy to use. It's great if you want to convert your DVDs for ipod, zune, etc.. Plus it's a great quick and easy converter for other formats too..
How big it the mp4 file? If it's under 100mb then you can ftp it over and I can convert it for you.
(Message edited by dcervenka on November 22, 2007)