welcome to maya and these forums

the help files would tell you the answer

do you know how to assign a material? (you just hold down right click on your object and select it from there)

when you do that the new dialog that pops up will have the option to add bump from a file
there are default bumps that come with maya
you can make your own bump maps to
there probably are downloadable bumpmaps, and there might be some in jpeg format, i've never looked (why waste time searching when you can create your own in less time? )
i assume you know what a bump map looks like? they are greyscale pictures

you should take a look at the tutorials that come with maya, you'll have answers to a lot of your questions then