A good place to get unlocked phones, or to get a phone you've already got unlocked is the sellers on the howardforums (
www.howardforums.com) under the "promote yourself" section. I've bought a few phones from lvwireless, and he usually beats ebay prices by anywhere from $15 for the really hot phones, to $75 for phones that are oddly overpriced on ebay.
I know if you're a VS customer, with a voicestream phone, and you're a customer for something like 6 months, you can e-mail them at
SIMUnlock@voicestream.com with some info (your account name and #, and the phones IMEI number, which is usually located on a sticker, on the back, under the battery), and they will give you the unlock code. I've actually read that if you get, say, a v60g, they will unlock it a lot sooner than 6 months, because its a world phone, and one of the features they advertise is that it can be used anywhere.
Odz - About buying phones here and using them in spain, make sure that the phone you buy here (if you do) is a "world" phone, or at least one that works on 900/1800mhz. A large number of the phones sold here ONLY work on 1900mhz, and therefore won't work in spain.