I believe an excellent song for soloing in the full minor key is Black Magic Woman by Santana. It has solo parts that you can learn, but is also a generally welcoming song to improvise on top of.

I'd also consider Dream On by Aerosmith. With some simple fills and more tricky short solos, it has something for guitarists of many skill levels.

While not entirely in a minor key, there are some excellent minor-key soloing licks to be found in Hotel California by The Eagles.

A lesser-known song that has some great minor solos in it is the studio release of Hey Baby (New Rising Sun) by Jimi Hendrix (look for it on the recently released First Rays of the New Rising Sun album, also on Voodoo Child - The Jimi Hendrix Experience).

All of these tunes use the natural minor key; while I am not a music theory expert, it sounds to me like Hotel California employs all three minor flavors... it's in Bm but features a sharp 6th and 7th in its progression.

Good luck!