
Palm Addicts has a
nice roundup of available PDF viewers for Palm OS. Those readers include:
Adobe Reader,
Metaview,
Repligo, and
Documents To Go.
Personally I try to convert any PDF document on a PC desktop first (using Adobe Acrobat) - preferably into HTML - and then to use one of the various offline HTML readers (e.g. iSilo or Plucker/Sunrise) to make the document available on my PDA.