What genre of music would this be considered?

Song 1:

http://www.youtube.com/watch?v=Nemst-oB3Po

Song 2:

http://www.youtube.com/watch?v=UskSU5BoyZs

Song 3:

http://www.youtube.com/watch?v=bRLCSxSR39s

What type of genre would these songs be considered?

Also what are some similar songs/artists?
(ones with the duet stuff would be best but all that sound like these
are good)