Adobe Document Server
demo for the application that allows users to view, navigate, and search PDF files in nearly any browser without Acrobat Reader
PdfMagic
acrobat plug-in that converts PDF documents into text
PDFzone.com
online hub to all things Acrobat and PDF
Planet PDF
provides articles, tips, tricks, FAQs, and more
Search Adobe PDF Online
search engine for PDF documents that allows you to view the summaries before viewing the actual documents
xpdf
a free PDF viewer for X (UNIX and VMS)