If you are not looking for 5.1 and are just going to have 2 channels, just buy a set of wireless speakers which should hook right into the RCA jacks.
here is a set & if you do a yahoo search for "wireless speakers" Im sure you can find cheaper ones.
http://www.circuitcity.com/detail.jsp?oid=70396&WT.mc_n=4&c=1&b=g&u=c&WT.mc_t=U