Hey Kats,
There are lots of clubs in SL that frequently hire hosts and train them. Dancers are a bit lower demand in recent times.
The best way to find a job is to hang out in places where you like the music and atmosphere, and make friends with the people on stage (as well as regular patrons). By building up a reputation and knowledge of SL in general, and the club specifically, you will be a natural candidate when there are openings.
On a side note, most host jobs make between $L200 and $L1000 for 2 hours of work, that converts to roughly $1-$5 US, so if you're looking at a job for the money it's better to become a creator than a host/dj/dancer.