^^^^ everything Chris said plus:
I rate the low-middle end canon bodies, for the money they are great. The 400d will do you very well. It may be worth shopping around a little bit though, the 400d is a good camera but is 3 generations back from the current model (400d->450d->500d->550d) so expect to not pay too much!
I bought a 450d package with 2 lenses quite some time ago now. There were the EF-S 18-55mm and EF-S 55-250mm kit lenses included, and both have image stabilisation (you want this!). I found the 55-250mm was something I used a lot more than the 18-55, I didn't really use anything below 55mm except on occasion when I wanted to take in a landscape etc. It does depend on what you want to photograph most, so give that some thought and let us know so we can advice you more appropriately.
Also, it's worth checking whether this lens has image stabilisation, as I think the earlier models didn't come with it as standard but I can't remember when the image stabilisation came as standard...
18-55mm will essentially provide what you may be used to with a compact camera, good for taking a lot in but not so good when you want to zoom in on something and fill the shot with it.
If this is cheap enough it will probably be worth going for it, I would imagine regardless of the lens you get initially after a little time using the camera you'll probably want a more expensive lens or 2 for specific use. The 18-55mm will be fine for the beginning of your photography learning adventure
edit: Just for info I have the 2 lens above but also bought these below, reasons given so you can understand things a bit more:
- Tokina 100mm AT-X F2.8 Pro Macro (http/www.shutterbu...ses/0106tokina/) - I use this for 1:1 close ups, it is a "true" macro lens and has a very short minimum focal distance of around 30cm. Still getting to grips with it but it is useful for taking shots of the fish and small things as well as great portraits etc when out and about.
- Sigma 150-500mm f/5-6.3 DG OS HSM (http/www.stockholm...sigmapage1.html) - heavy! need a monopod/tripod regardless of image stabilisation being there. This is my new toy and I am slowly getting to grips with it. Probably the most money I'll ever want to pay for a lens. Great for medium to long range shots, I'll be using this more as the light improves when spring finally arrives, where I'll be roaming around the Norfolk Broads (7 miles away from me ) and visiting some wildlife reserves and zoos.
I hope that all helps a little...