I have a list of free resources a mile long, but these are the ones I use all the time and can't live without.
www.logmein.com - remote access server
www.myhours.com - time tracking
www.google.com/calendar - online calendar
www.officelive.com - free website domain and hosting, and online office where you can upload excel and windows files
www.toolbar.google.com - i love this thing, you can download anything to it, i have a spell checker on mine so i can spellcheck anything anywhere, bookmarks that i can access anywhere, websters dictionary, etc.
and of course, it goes without saying...
www.virtualassistantforums.com!