Google and AltaVista already offered this kind of service for many years but the new translator service from Microsoft, which is powered by Systran, looks pretty good.
One of the things I like a lot about this service is that when you translate a website it shows the two versions next to each other.
Microsoft's Windows Live Translator offers support for a broad range of languages and there's even a "computer related content" checkbox. The service is still in beta - it doesn't work perfect - yet but it looks promising.