Daily comic strips and manga.
GoComics
www.gocomics.com/ (xhtml-mp)
Hundreds of popular newspaper comic strips including Doonesbury, Garfield and Calvin and Hobbs as well as editorial comics from Pat Oliphant, Dan Wasserman and others plus a large selection of comics en Español.
Both current and previous days strips are available. The site supports zooming in which is a good thing as the strips are too small to read at the default zoom level on most phone screens
Manga Fox
m.mangafox.com/ (xhtml-mp)
Read Manga (Japanese book-length comics) of your phone. Magna Fox has the full text (with English translation) of over 50 manga. They are displayed one page at a time as 320x480 images. Because of the size of the images and the average 50 KB page size, Magna Fox works best on smartphones with a high resolution screen like the iPhone, Nokia N97 or Android phones. Source: Oh! Mobile Directory
Stripr
dbelement.com/stripr/ (xhtml-mp)
View your favorite daily comics in your mobile browser with Stripr. You can customize your Stripr by choosing from over 150 different strips including geek classics like xkcd, Dilbert and Apple Geeks as well as some mainstream comics and some really obscure ones. The comics are pulled from user submitted RSS feeds and not all of them work. Check the user ratings which are a good guide to which ones are functional.
Billed as an iPhone webapp, Stripr also works well with the Android browser and Opera Mini. You do have to register to use Stripr but registration is free and only requires an email address.
12-Jul-2013: Very few of the comics links on Stripr work any more. One that does is xkcd
Yellow Peril
ypcomic.mobify.me/ (xhtml-mp)
Online office romance comic Yellow Peril and its creator Jamie Noguchi's blog in a mobile view created with Mobify. The Yellow Peril comics combine several panels side by side in a single JPEG image. Mobify re-sizes the image to fit device screen width which makes the text too small to read on most devices. Jamie solves this problem by providing a text transcription below the panels which works out pretty well.
12-Jul-2013: The Yellow Peril mobile web app is currently broken. The pages load with banners and text but the conic strip panels are missing. Hit the "Go to full site link to see them".