For British Isles, forget the solar charger idea and, as Brian and Roy say, use rechargeables. Time was when LiIon were MUCH more expensive than AAs but nowadays, like 2-gig memory cards, the prices have fallen through the floor. I've been buying such bits from
http://www.7dayshop.com for years and had good service and great prices. At 1 gig for a fiver (and 2 gig from about £15) it isn't worth buying a smaller card. (They sell cameras too.)
Resolution: if you shoot at any less than maximum resolution, you limit the uses to which your images can be put. For viewing on screen, of course, it doesn't matter (72 dpi) but as a publisher we are constantly frustrated by folk with what look like good and relevant images that turn out to be lo-res and therefore unusable (we need 300 dpi). Better to have a large card and delete duds from time to time.
For camera choice, it's a fast-changing scene and I'm reluctant to say much: I agree with Brian, I keep camera in trouser pocket or on rucksack waist strap. The best website for digicam reviews I've found is
http://www.dpreview.com/ and their weekly newsletter is brilliant (over 120,000 subscribers!). Good glossary etc if you are new to dpi, stabilisation and megapixels. BTW digital zoom is a con, you can do that on any computer screen, just go by the optical zoom and (to avoid camera shake without use of a tripod) some kind of image stabilisation at long telephoto lengths. Whatever you decide to buy, you will learn from it what features you'd really like in your next digicam: good luck!