I would check out
http://androidarts.com/cortexcommand/ as he was the one that did the art for Cortex Command (and I think Planetoid Pioneers?). For googling about how to do the pixel art style, there's a tons of ways to do it. One easy way I found was to draw large simplistic representations of what you want to do, resize it to sprite size and do small fixups, check this thread:
viewtopic.php?f=1&t=16881 for that. From a spriting focused way, check this:
viewtopic.php?f=1&t=45643&hilit=spriting