One of the best ways I've found to make some residual income is by asking and answering questions on webanswers. It's really easy to join and as the site doesn't pay you directly, but rather helps you get Adsense impressions, it really helps you out by assisting in the application process for getting a Google Adsense account.

If you are good at answering questions and prepared to do quite a bit of work and produce quality answers then you can earn $300+ easily. It's a secondary site for me, and after creating a decent portfolio of answers, I tend to add about ten answers a day and still earn close to $100 a month.

It's not a get quick rich scheme but a good way to earn some residual income and also get a Google Adsense account.

You can join by going to Webanswers.com - there's a link (with my affiliate code) on it in my profile if you want to use that - no need to though if you don't want to - the site could benefit with more decent members anyway.