Here's a roundup of various (clearly not all) photo editing apps... I didn't have full review on these yet, so here's some early impressions:
Pho.to Lab http://www.appbrain.com/app/pho-to-lab/vsin.t16_funny_photo
Beautiful Pictures http://www.appbrain.com/app/%E7%BE%8E%E5%9B%BE%E7%A7%80%E7%A7%80/com.mt.mtxx.mtxx (this title is in Chinese)
PicsIn Photo http://www.appbrain.com/app/picsin-photo/com.photo.picsinphoto
Photo Wonder http://www.appbrain.com/app/photowonder/cn.jingling.motu.photowonder
Little Photo http://www.appbrain.com/app/little-photo/com.littlephoto
There are a few more, like PicPlz, Photoshop Express, and more. I'll add them as I find them.