Con,
There will be plenty of testing in Spain in the run up to the opening F1 race in Bahrain. Formula 1 teams will be testing at 3 tracks in Spain during February.
At Jerez: 7th to 10th (Tel: +34 956 151 100 ) -
Official Site
At Barcelona: 13th to 16th and 20th to 24th (Tel: +34 93 5719700) -
Official Site
At Valencia: 29th Jan - 3rd and 14th to 17th and 27th to 28th (Tel: +34 96 252 52 20) -
Official Site
There usually is a small entry fee (5 - 10 Euros typically). On some days you can book on a guided tour where you are taken around the track with a guide.
Tickets are sold at the gate.
Note these are all provisional dates and can change. Confirm with the track before going.
Hope this helps