I'm asian and travelling to Spain for the first time...would appreciate if anyone could tell me how to get to Lisbon from Seville or Cordoba. Is Granada worth visiting....I would be travelling by railway for 2 weeks, any advice?

Granada is worth visiting, the Alhambra and the Generalife are beautiful. You will need to purchase your tickets in advance.

I traveled by train from Corboba and Sevilla, I would recommend it. Here is a website to locate connections to Lisbon. http://www.renfe.es/ingles/index.html

i tried the RENFE site but it doesn't show travel to Lisbon...
i'm now undecided between joining a tour and travelling by coach or travel freelace by rail...any advice?...thanks

Try http://www.cp.pt for Camonhos Portugueses te Portuguese railway website. There's an overnight train, the Lusitania Express between Lisbon-Madrid and there's also one that runs from Porto, Portugal northeast thru Spain.
You might also want to check out Eurolines (Bus) http://www.eurolines.es click on Portugal. They have service Sevilla-Lisbon about 4-days a week. Before you go, contact my friend Carlos Ferreira Restrela@esoterica.pt for his Residencial Estrela do Saldanha in Lisbon: Centrally located, clean and comfortable (and very economical). I could have written 'cheap,' but the alliteration might do me in for the day.