Brussels' bike hire scheme, Villo!, started a few months ago. It's the usual deal - register online, pay a fee, then use your credit card to take out a bike from one of the docking stations (right) and return it to that one or any another. The yearly sub is a bit steep compared to other schemes at 30 euros, but the first half-hour of rent is free. They claim 2500 bikes at 180 stands all over the 'Brussels region', which surely must be 'Belgium'?
The Villo! website looks good, and (are you listening, Krakow?) provides thorough versions in English, French and Dutch.
I had a brief encounter with Villo! during a six-hour wait between Eurolines coaches, shuttling between Brussels-Noord and the Grand Place. Not many people using it, but it seemed OK. (The layover was otherwise dismal, unpleasant and sinister, though: backstreet-city Brussels in the dark is not enjoyable cycling. The football hooligans down by the Grand Place were somehow reassuring by comparison.)