The ability to view PDF documents is limited to emailed attachments. You can not open a saved document.
BlackBerry Attachment Service - 290 Kb
Quote:
Attachment Services
Attachment Viewing
Get all the information you need while you're on the go with the ability to open and view email attachments on your BlackBerry device, whether you have integrated your device using BlackBerry Internet Service™* or BlackBerry Enterprise
Popular Attachment Format Support
Microsoft� Word
Microsoft Excel
Microsoft PowerPoint�
Corel� WordPerfect�
Adobe� PDF
ASCII documents
HTML attachments
Images: JPG, BMP, GIF, PNG and TIFF
File types listed above archived in .zip format ...
What BlackBerry fails to address becomes an opportunity for the third party software vendors.
BeamBerry is a subscription service that enables PDF viewing of downloaded files.
For less demanding results, the free MobiPocket Reader will import PDF files for conversion to an eBook format. They can be saved to the media card and viewed as required.