I never did get into web comics much. But most any good Paint software will prep a drawing
for the web after scanning it into your computer, unless you create it there. I generally go
with .jpg since they can be small files. If you don't have any experience with .html. You can
get software that will do most of the work for you. GoDaddy hosts websites and domains if
you like. Or you can post on art sites, or even with a Facebook page.
There are a few free html editors out there. Even the kind that shows what the page
looks like as you build it.
I would however suggest you start out doing a comic in black and white. Color though
pretty add significantly more work to it. You can always change to color later. or have special
editions in color.