How can i set up my canon eos 30d for plane spotting?

the 30d is a great camera but i've had alot of problems with it. i take pictures of planes but every time i upload my pictures to airliners.net they have too much noise or grain (like its over sharpened). i always keep the ISO at 100 but it still looks too grainy. i tried lowering the sharpness and it still has too much noise. i like to shoot at AV but my pictures look too bright. i want to take professional pictures like the ones on airliners.net so if your a plane spotter and you have a 30d like me please help!! thanx