I've used Companeo and ServiceMagic before but not sure whether I'd be enthusiastic about using them again in the near future - a Google search for the services which I offer doesn't place either of them on Page 1 and that's where my potential customers are likely to look first. I'm aware that they also do e mail marketing but I don't think that they're right for me at the moment.
There aren't any others that I know of or have used - OJEC is worth checking periodically for sub tender opportunities and there are a number of sites, free and otherwise, which will allow easy access and search facilities.