You know that awkward moment when you click a link in your DSi or 3DS Browser and it pops up saying Unsupported file type? Well, Nintendo didn't help you read your PDFs by including a simple reader with the system, so I'm covering. Optimised (UK English FTW!) for the DSi Browser (3DS version coming soon), read as many PDFs as you like. I'm adding some polish to it soon, but in any case you just want the link, right? http://hatenagain.heliohost.org/pdf/ (I'm going to move hosts soon, so don't get used to that link). So have fun. Files and rendered pages get cached for 12 hours. Have fun.
I'm going to add zoom when I have an hour free. This will also work on other devices, such as 3DSes (well, not 3DS because of a charset issue, a fix is on the way) and PCs.
It's an interesting concept, but the sample DSi manual didn't scale well with all the small text. There should be an option to specify larger image sizes that can be zoomed on the DSi.