RFC-Editor

Contains RFC news, search feature, details of the RFC-Online Project, and ASCII and PDF versions of all documents.
http://www.rfc-editor.org/

RFC Search

A search engine for locating RFC's and Internet-Drafts.
http://sunsite.cnlab-switch.ch/cgi-bin/search/standard/nph-findstd/

RFC Index

Index of all Requests for Comments.
http://asg.web.cmu.edu/rfc/

RFCUtil

Perl script allowing access to RFCs by number and full-text search of all documents. It features command line switches to spawn lynx or w3m to view the RFC, dump to file for offline viewing, or mailing to an address.
http://www.dewn.com/rfc/

RFC Search

Allows searching of the RFC index by number of keyword. Supports regular expressions, case sensitivity, and field searches.
http://www.nexor.com/rfc_search.htm

RFC Viewer

An RFC browsing utility for networking program and protocol developers.
http://www.effetech.com/rfc/

Zvon RFC Index

Repository of RFC's in hyperlinked, colorful HTML format; table of contents appears in separate frame.
http://zvon.org/tmRFC/RFC_share/Output/index.html

RFC.net

Weekly-updated mirror of the RFCs and STDs. Access to text and HTMLized versions, indexed and retrievable.
http://www.rfc.net/