The following web cam links will provide views of Algarve beaches :

Martinhal beach, Sagres

http://www.portugal-webcams.com/webcams/webcam-sagres.htm

Salema beach
( Still a working beach as well as a tourist spot - watch the fishing boats returning in the morning )

http://www.portugal-webcams.com/Salema/webcam-salema-mega.jpg

Porto da Mos beach from Hotel Vivenda Miranda
( A West-facing cam which often gives views of beautiful sunsets - pity about the cranes !! ))
(if you go into the hotel site, you can choose from 3 or 4 camera angles )

http://www.vivendamiranda.com/webcam/webcam-lagos-mega.jpg

Praia da Luz web cam
( Situated in the window of Bar Habana on the Luz promenade; note that the temperature shown is the ambient temp. at Faro airport - it's normally much warmer in the resorts in the sunshine )

the following link gives access to several cameras

http://www.madeira-web.com/camera/cam-01.html

http://www.climaat.angra.uac.pt/WebCams/index10.htm

thanks to Sagres