To answer like the rest, one really shouldn't. I mean it'd be pretty bad if you put a good deal of work into making one, and no one shows up. That there's the hardest part.
use zymic, i`m making my site with zymic complety on my dsi. Plus, zymic isn`t a cheap cheesy website builder like onmbl or webs...Zymic uses files for pages and supports mysql. So,if your a begginer, i would use something else, bucause zymic has no "website building tools".
Yes, to make a website for the dsi, you have to make the viewport a width of 240. Then i use adobr dreamweaver, wonderful program for making websites. :D
Graphics don`t make a game. dsi-web-friendly.webs.com! 10000+ visitors and counting!