======= Date Modified 10 Jan 2011 18:27:59 =======
If it were just any text that you want to understand, I'd direct you to the word reference forums or even a try with the google translator may give results that you can understand.
If it's official documentation, however, you will need it notarized. Always ask what it takes for these docs to be legally valid at the embassy or consulate of the country you are presenting you papers to, since not all countries have equal requirements. At the very least, you will need an official certified translator, and sometimes you will need a notary to put the necessary seals on your document.
As for pricing, it's usually a per word bill, though in the case of legal docs it may be more because sometimes very specific paper and ink and stuff is required. It will depend on the complexity of the document, and on how rare the target language is.
For english to spanish translations, these guys are good enough: http://www.trustedtranslations.com/spanish-language/english-to-spanish-translation.asp , though you can ask for quotes on other languages as well.
That's been my experience, though there are many agencies and freelancers out there... google is your friend! I'd start by asking in the embassy of the country you'll be presenting your docs to, they'll direct you to a proper translation service.