Relax Grazie, batch conversion was the right answer :-)
Julie, as you've discovered, Vegas won't recognize PICTs (originally a Mac format) files.
If you've got Photoshop 7, you can do a batch process (File > Automate > Batch). If you've got an earlier version, simply record a macro for doing this. I'd save them out as PNGs as Vegas likes that format.
I'm no Photoshop guru by any stretch of the imagination so if I figured out how to do both of these processes, you can too.
1) Make sure you have Quicktime installed- the free version is fine, confirm you have the authoring components (which is not a default during QT install).
2) In Vegas' explorer, choose the "All files" view. Picts will show up.
3) In the case of image sequences, use "Import Media", again you'll need the "all files" view. Click the first image in the sequence, check the "Open still image sequence" option... off you go.