Layer tutorials

I'm using PS7 (and hopefully CS3 soon) and played around a lot with blending layers lately. I've also tried my hand at adjustment layers and while reading a tutorial a couple of days ago (or the comments to a question?) about setting an adjustment layer to screen. It made me wonder if there were any general tutorials on adjustment layers and with which settings they work well (so far I only used Normal at 100% most of the time). I tried looking in the memories, but didn't find anything that could really help me (and I'm hoping I didn't miss anything obvious there)

I'm not someone who can go step by step on tutorials as I'm someone who wants to play around a lot and I need some understanding/inspiration on how I can use adjustment layers to get more out of it than I'm doing now.

(Also, anybody who could supply me with a link to a list of English-German translations for the different modes would be loved. Soft Light might be easy to translate, but some of the others aren't)

EDIT:
Since I got a comment about saving as a .png instead of .jpg... is there such a big difference?