Google features a whole bundle of decent free applications, either directly under Google's aegis or using a contraption they call Google Apps. Apps allows you to bring your own
domain name; the main benefit is that your email address is more personalized and professional-looking. It is straightforward for Apps users to share things like calendars semi-privately, ie only with others under that same domain. One drawback is that Apps accounts do not offer as many features as regular [Google] accounts: only Mail, Calendar, Docs, Talk, and Sites - although this set is about to broaden. For small business use, though, this set should suffice for many people. The only unfortunate thing is that Google recently reduced the free limit for Apps to only 25 users, not large enough for a number of nonprofits. Note: ads in Apps Gmail can be toggled off without having to pay, if you have Firefox - just get Gmail Without Ads extension!
I use:
* = not accessed via web browser (must download and use on standalone computer)
Last updated: 20100728