Perspective Correction in Photoshop 7

[another view]

I kept an article in Popular Photography (can I admit that I read that?) on how to do perspective correction in Photoshop. I kept it in such a special place that I can't find it. Also checked Scott Kelby's book and can't find anything there. Anyone familiar with this?

I want to straighten out the building in this shot so it doesn't look like it's falling over - I shot it on medium format with a 50mm (wide angle) lens pointing up a few degrees, planning to do this technique later (or much later as you can tell). Thanks in advance.