Well, there is no built in way. I needed to copy a bunch of them from one provisioning portal to another without much grief (it was a client’s portal, and there was no offline list available). So here’s what I did. Using Safari on OS X:

  1. Log in to your iPhone Provisioning Portal
  2. Click on “Devices” in the left sidebar
  3. Click on the “History” tab
  4. Select all the items under the column headers, then “Copy” to your pasteboard
  5. Launch “Microsoft Excel 2008” (tested in Apple’s Numbers 2.0.5 (368) as well)
  6. Select cell “A1”
  7. Paste the contents of the pasteboard in

Now all your UDIDs are properly formatted in columns!

Edit the ones you don’t need, etc, based on the “Description” column. To export the list for another portal, you will need to move the column “Device ID” so it is before “Device Name”, and remove the other columns. You will need the first row for the column names still (first row is ignored by the importer). Then export the spreadheet as a tab-delimited text file. Now the UDIDs are ready for import.