You can preflight your PDF using most design software - at MOO, we normally use Adobe Illustrator or Photoshop. To preflight from these programs, you can follow these simple steps…
- Open the file (preferably the .ai or .psd file) in the relevant program
- Click "File>Save As"
- Select "Adobe PDF" as the file format
- The "Adobe PDF Preset" menu will then pop-up - select [PDF/X-1a:2001] from the dropdown
- Click "Save PDF"
If you do not have a copy of Illustrator or Photoshop, you may find some useful information in the Adobe Forums.