Hi, Monita,
Have you read the thread called Aragonese Pyrenees? It's here in the Favorite Places sections, a few thread down.
I strongly recommend Jaca, after spending numerous vacations there at different times of year. I have never come across any other pueblo like it in Spain. Not only does it have loads of history, great architecture, monuments, and museum collections, it has cultural offerings few pueblos its size can match, not to mention countless sports opportunities. It's in a beautiful location, and it makes a wonderful base for more exploration of the area. The restaurants are excellent, there are bars and pubs galore, the tapas and the pastries (oooh...the pastries....) - well, you'll have to experience it yourself!
These websites are in Spanish, but they are helpful.
http://www.aytojaca.es/ http://www.jaca.com/ There are plenty of places to stay, but it does fill up in July and August. The office of tourism is very helpful, and they speak English there if the Spanish is a problem. French is widely spoken because of its proximity to France.