Its an interesting question. We've seen international interest grow on our website to roughly 5% of use coming from outside the US. Its primarily search engine traffic, which tells me that there's some level of interest. But of the half dozen Europeon sales that we've had this year, all have come from direct referrals. So, my advice would be similar to the other responses, find a Realtor with experience selling abroad and whose website has Europeon traffic.
Although I think Gail's answer is great I am wondering why not have your real estate agent advertise the property online? There are many directories, blogs, and other web resources where you can list your home. If there is anything else I can do feel free to ask.