I have the a300, so I think they're pretty much the same?
It all depends on what kind of photography you're aiming to do. I don't really know of any sites. I learned by doing, but what I've picked up on seems to work.
The main things you need to know how to work are the Aperture and the Shutter Speed when you're using an SLR. General rules are the lower the aperture (f.stop) the more bright and vivid your pictures, the faster your shutter speed the crisper your pictures will be.
A: The Wheel of Fortuuuunnneeee! I figured the best way to work out how to use my camera was to avoid all the pretty picture options and go straight for the letters (mainly M, because you control everything then).
B: This camera isn't set to Live View (which gives the preview on the screen of what you're shooting at). But it means you can see the screen information easier! The 1/250 is the shutterspeed. 1/125 or 1/250 are pretty okay general purpose shutterspeeds. 1/400 is what I use when taking BMX or skateboard photos, as it catches stuff in motion pretty crisply but still lets light and colour into the shot. For night photography I use a tripod an a shutterspeed of 1/4 or go all the way into the seconds range. The "F5.6" is the aperture. I still don't have a clue how aperture works but I tend to always use the lowest aperture possible as it lets colour in. If in doubt about it, use the "S" setting, as it has an automatic aperture control (but I don't think it's that great).
C: This wheel controls the shutter speed. Move it to the left to lower it, to the right to make it bigger.
D: Hold this button in whilst using
C changes the aperture!
And, well, that's all I've really learnt.
The wikipedia pages seem to have decent information on
shutterspeed.
But yeah, I don't know a thing about ISO or lenses. That's about all I've learnt in 6 months of using the Sony Alpha. Hope it kinda helped in some way.