Website building
From Cashwiki - the Collaborative Website about Money.org, the Money Wiki
Making websites can be a good source of income. You can construct websites through CMS systems, such as
All you need is a web server and the ability to construct these things. Knowledge of Linux can come in quite handy, although you can also use servers that are based on BSD or even Windows (not recommended by Cashwiki.org) servers.
See also this post on Slashdot