Yes, nine cents so far, just switched on adsense for my two sites
www.americanguitars.co.uk and
www.teecaddy.co.uk
W3 Alliance are really good people to deal with, very professional and everything is exactly as they say it is, completely genuine.
Quite a lot of work involved, it is certainly not money for nothing. If you are prepared to work at it, I'd say it is worthwhile.
Don't be sceptical, they are completely up front, if you make the effort they will hold your hand all the way, but don't waste their time if you are not serious, they are just not at all interested in the half-hearted.
You have no outlay at all, just hosting costs, and they really earn their share of the income, if there is any. Allow an absolute minimum of two to three months of fairly hard work before you see any results.
But ask me again in a couple of months, I've still got a lot of work to do!
Whatever happens, it has been a really enjoyable learning experience and I would recommend it without reservation. (well, maybe the hard work bit ;-))