Personally, I'd be leery of a multi-level marketing scheme in general. Here's a cautionary note about Zrii from scam.com:
http://www.scam.com/showthread.php?t=31339
You might want to read these guidelines on determining whether a MLM scheme is a scam from the Federal Trade Commission before looking into something like Zrii:
Multilevel Marketing Plans
The moral is: do your homework, and be careful. Also be careful of internet "work at home" schemes that promise income for stuffing envelopes and the like. Achieving success on the internet requires something to sell and effort building your business, like everything else.
What skills do you have, and what market niches can you fill? If you have a craftsy or artistic bent, you might make something unique and sell it on eBay or even set up your own website business and market it. If you are a writer or editor, you can freelance your skills on boards like eLance and Guru.com. All of these will require some investment of time and money to succeed, so beware of those who promise to give you something for free. There Ain't No Such Thing As A Free Lunch.
Vasily