A good source for welding information is
http://www.hobartwelders.com/mboard/
Just search around before posting, as most beginner's questions have been discussed several times.
And here are some tips:
http://www.lincolnwelding.com/knowle...icles/list.asp
I recently got a Lincoln SP-175+ MIG welder, primarily because I wanted to be able to do 1/8 to 3/16 Aluminum if necessary. If the cable is kept straight and the wire feed is set up correctly, a spoolgun is not absolutely necessary. The stiffer filler alloy is preferable (5356?), as is a larger diameter wire, to prevent kinking.