The xml field definitions are here: http://www.ubercart.org/files/cck_fields_export.xml

Or you can install the uc_importer.module and do a single product export, then take a look at the generated xml file. The xml is pretty self-explanatory.

I'm going to be writing something today which will convert my csv product file into xml. It'll be a bit of (standalone, for now) php code which will take csv as input (initially by pasting into a textarea), do the formatting stuff and then give xml as output (either in pre tags or in a textarea again). I've defined some extra CCK fields within my product type so my solution won't suit everyone. Step 2 would be to map csv fields to CCK fields dynamically - I guess since this is something a lot of people want right now there'd be a bit of demand for it?

Lyle, shall I go ahead and upload this as a contrib module once it's done? It won't be anywhere near mature - but the version I'll upload should help prepare a csv file for import into the vanilla product definition.

As for your other question, druru, why not import the csv directly into the database? Good question! I haven't looked at the uc_import module much yet, but that's the code that Lyle has written and I'm happy to work within it. If you want to go ahead and write your own csv importer, go for it Just make sure you generate the hash key in the correct way (line 762 in uc_importer.module)...