I don't remember where it is, but Sheldon Brown talks about a home frame alignment technique. It works like this, I think:

Take a string and run it through the rear dropouts and around the head tube, making a triangle. Pull it tight. Take a ruler and measure the distance from the string to the seat tube on each side of the frame. This should tell you whether your frame has a lateral bend.

I'm not sure how to check for other bends except by eyeing it.

I hope the bike's at least rideable. I've ridden bikes that rode just great as long as you kept a hand on the bars, and hopefully that's the case with this one.