IPhone 4 with a PUK lock. Is there any way to unlock it?

I found an iPhone and I'd like to use it.

Or if possible to unlock the 4.12.1 baseband so any SIM card can be used with it.

Added (1). It was found in Canada and its service provider is a DUTCH company. I did not steal it. What happened to finders keepers?

Try to return instead.

Wow, it seems like everyone is starting to turn into thief's now. I hope you get caught.

edit: So wait, you didn't steal it, but yet you'd "like to use it"? Yep, you sound like a thief to me.