I searched the forum, but couldn't find something on the question, that tortures my drying brain for the last two weeks:

How do I create beautiful old paper textures for fantasy like or medieval looking A3-maps (or bigger) with photoshop?

I've got Photoshop CS2 (loaded it for free from the Adobe site three days ago) and would like to know some tricks or good
ways to create the look of dirty, hand made, old paper.
Are there any tutorials or descriptions to do that? Or are there even free collections with ready made structures?
Do you have a hint, which photoshop filters or functions are good to work with?
Is there an alternative to photoshop (got an A4-scanner)?
How do you do that?

Please help me.