Aluminum is the metal that humbles the proud. OK, I'm not that proud but I do have enough experience with stick and O/A on steel to be relatively handy. TIG welding is so darn useful that it was an obvious next step for me. Having some O/A time on thin stuff like autobody and exhaust helped; TIG on steel felt a lot like a really versatile blue-tipped wrench and wasn't too hard to get above the embarassment level. Sooo I forayed into ally.....wow is that a different world! The inverter helps tailor the setup to whatever I'm tormenting but there's no substitute for experience. If someone showed me good aluminum welds with a buzz-box-anything I would think they were a welding god. I can't even begin to think of trying that except for entertainment purposes.
See if your local community college has night classes in welding. Several years ago I took one at the CC and it's money well-spent. You get to play with some decent gear and have an instructor show you the ropes and critique your technique. I want more classroom time but they succumbed to the allure of stimulus money, $1.7 million worth and killed the weekend-warrior classes in favor of a six-month career program.
I agree with Sundown that the Miller student literature will go a long way to educating yourself but you'll also need suitable equipment. A transformer stick welder will just frustrate you.
Harris dual-stage O/A
Lincoln AC/DC buzzbox
Miller 3035 spoolgun
Thermal Arc 185
Thermadyne Cutmaster 52
Angle grinders, vicegrips, the usual suspects
Two hands, tired body, not enough time...