I'm a great fan of Canon cameras. I've got a 'little' (but by no means tiny!) Canon A85 (4 Mp) and a Canon 300D SLR (which is quite big and heavy - especially with extra lenses). I carry the A85 around with me for day-to-day use and the 300D on holidays or for my occasional botanical field trips (like the one I went on today).

Both cameras have both automatic and manual controls and are supplied with really excellent documentation and software (both of these are a must, in my opinion).

The A85 is a couple of years old now and has probably been replaced by similar models with a higher spec. I couldn't tell you what the latest models are but they will probably be in the "A" series. They will also be a bit 'chunkier' than the super-slim "Ixus" range and will have a dial on top with a comprehensive set of settings and some have a fold-out screen as well (not present on my A85).
I would look for as many Mps as you can afford (4 or higher). Some 'puritans' will tell you that you don't need this sort of resolution but I find that it can be useful if you want to zoom in and crop pictures in your image editor (something that the 'puritans' tend to forget - or perhaps they're such perfect photographers that they don't need to crop!).