Internet Utilities
Online Tools
Password Encrypter - Encrypt passwords for .htaccess files, etc.
Link Popularity - See how many sites link to you, and how your links compare to other websites.
Third-Party Tools
Alexa Toolbar and Website Statistics
Offsite Links
Robots.txt Validator:
www.searchengineworld.com/cgi-bin/robotcheck.cgi
Find Duplicate Website Content (e.g. sites copying your content):
www.copyscape.com