Composers can send in songs to the national public broadcaster RTP until the 12th of January. Songs have to be written in Portugese and only songwriters and composers of Portuguese origin are invited to send in songs. You can read the rules here.
Website visitors will then cut down the 24 compositions to 12 songs between 19th and 30th of January. For four weeks, the chosen ones have the possibility to improve their productions and act. Finally, viewers at home and a professional jury will each get a 50% say in the outcome of the Portuguese national selection for the 2009 Eurovision Song Contest.
In 2008, Portugal was represented by Vânia Fernandes, who sang Senhora Do Mar. For the first time since the introduction of a Semi-Final, back in 2004, a Portuguese contestant qualified for the Final of the Eurovision Song Contest. Fernandes finished 13th.
Thanks to Alexey Uvarov for providing us a link to the document with the rules.