If you live in a rural area away from the main telephone exchange you probably won’t get a mains telephone, therefore no ADSL connection. If you are lucky, you may get a radio telephone which for Internet use is 10 times slower than a modem (text emails only)
For nearly 3 years I used to take my laptop into the nearest town but now (praise the Lord) finally have ASDL via a wireless connection 7 miles away and this is increasingly becoming the way rural areas get access. I can also use iChat/ SKYPE /terra call etc with this service. It works on the same principle as an internet cafe (so you’re on a local network) only with everyone spread all over the countryside using their own computers.
Visit your nearest Spanish computer shop and find out if anyone in the area provides this type of service.
You need a direct line of sight to the mast so if you’re in a valley you may have problems. A new version of wi-fi is coming out that covers vast distances and is capable of speeds as fast as cable.
Be wary of some Brits advertising this service as you need a license to operate a telecoms service. Try and find a Spanish firm as you want a long term service
Other options are satellite and PC cards with GPRS but both are limited in cabability and are expensive
A new law was passed in Spain a few weeks ago that says everyone should have access to the Internet and acknowledges the importance of broadband to the economy and future job creation so things are starting to move and there seems to be a lot more options for people in the last year. As you plan to live near Sevilleor cordoba, you may well be lucky now or in the months ahead