Well just for fun I am using the updated mobile interface for wordpress which is not sexy but is practical. Actually I can use the normal website on my Itouch, but this would definitely be better for my humble phone.
Basic for now but could be handy. Find it at http://m.wordpress.com or using HTML at http://m.wordpress.com (which just might be too much trouble even if it works). However, if all you want to do is Post a bookmark, then you can just use the Bookmark tab rather than the post tab to do that.
Lets you add tags too and save drafts or publish, but you have to add categories later.
As we move slowly into mobile tools with students, this type of thing, and future enhancements, will become part of the core toolkit for 21st century learning – added to all the other uses interactive mobile devices allow.