From what qatarisun and vignale have mentioned I get to understand that you are seeking info about online jobs. Like they have already mentioned, dont trust the sites if they ask money. Having said that I would like to add the following.
1. If you have some programming expertise you could take part in the open source projects.
2. Write technical blogs

Both of these will be a good way of spending time online and can earn you money in the long run.