[zan]

Probably the easiest way to start is to put your camera on Av and the widest aperture you have (probably F4 or F5.6 on the 75-300mm). That way, the camera will automatically keep the shutter speed as high as possible, which is generally what you want to begin with (animals are quick wee things when you point a camera at them!).

Try and keep your shutter speed as high as you can (over 1/200s) is good as a minimum for fast things, which will reduce blur and shaking. If your shutter speed won't go that high (e.g. in low light), you'll need to increase the ISO (starts at 100 on you camera I think, and goes up to 1600?). This will make your photos a wee bit more grainy ('noisy'), but will increase the shutter speed. You should be ok up to about ISO 400, then you'll need to decide for yourself whether the extra noise is worth it.

Hope this is some help. This is what I did when I first started out and it was a good place to learn from. If you're not sure what aperture \ shutter speed \ ISO are though, I'd recommend getting a good book (like brian petersen's Understanding Exposure) or reading matt's beginners guide.

Good luck!
Zan