Being a fairly new webcomic artist, I know how frustrating it is to have such little information out on the internet about creating a webcomic. My style is pieced together from dozens of random tutorials scattered across the net- but it might help somebody to see it consolidated into one quick tutorial. Okay, step-by-step, here's what I do:
1. Draw a thumbnail copy of what the entire thing is going to look like in any random notebook or scrap sheet of paper. The less detail the better- just capture the essentials and figure out where the characters, speech bubbles, and background elements are gonna go.
2. Curse loudly because I've most likely run out of bristol paper.
3. Buy some more bristol paper.
4. Pencil in the guidelines, borders, and speech bubbles.
5. Using my thumbnail picture as a guide, flesh out the comic using a pencil.
6. For inking my lines, I alternate between using the following: a Newton & Winsor #000 brush and Bombay Black india ink; Pentel Pocket pen brush; and Pigma Micron pens. I use the traditional brush whenever there are a lot of curvy, broad lines to make, or when I'm in a particularly artsy mood; the Pentel is used primarily to ink my borders and speech bubbles, as well as close-up elements; and the Microns are used for small, detailed lines.
7. I hand-letter my comics nowadays, so I use a 03 Micron for normal text and the 08 Micron for bold text.
8. After not waiting long enough for the ink to dry, I erase all the penciled lines. (Extra points if the kneaded eraser I'm using is filthy. Points deducted if the ink smears.)
9. I scan the entire image in 600 dpi in pure black and white as a PNG image.
10. Using Photoshop CS3, I go to Image -> Mode -> Grayscale and convert the image into a grayscale. Then I use the Select -> Color Range -> Fuzziness max to select all the whites. THEN DELETE THE CRAP OUT OF THEM.
11. The black-and-white image will most likely look terrible if you zoom in 100%. That's okay- that's why you scanned your images at 600 dpi in step #9. At this point, I go to Image -> Image Size and set the resolution to 300. Now, if you zoom in, you'll find that the lines look much nicer. There are technical ways to explain why that happens and why it looks that way, but for the average Photoshoper, it's just a nice, time-saving trick.
At this point, you have a nice, large, workable black-and-white comic. There are dozens upon dozens of ways you can color, shade, or paint a comic digitally- if you look on Jeph's uStream, there's a tutorial for something called BPelt. That's what I use to lay down flat colors, but there are certainly more ways. (Note: To color comics in non-greyscale colors, you have to go back to Image -> Mode and choose RGB Color.)
Hope that helps somebody. I'm open to answering questions via messaging as well, if you've got any questions to ask. I've made webcomics with tablets, ink, brushes, pens, paper- basically all mediums, and I'd be more than happy to help you get started.