The availability of Google Streetview in Lisbon and Porto as from today was announced in the following article: (in Portuguese)
http://economico.sapo.pt/noticias/ruas-de-lisboa-e-porto-vistas-ao-pormenor-no-google-maps_67728.html
I have run a test on Google Maps with simple queries such as "Rossio" and "Marques de Pombal" it appears to be working.
