The Entire English Language Wikipedia has been converted to .mdx format from the latest wikipedia dump (30 January 2010). MDX files are read by the free program Mdict which is a dictionary reader available for WM Pocket PC, WM Smartphone, and HPC, also Win XP & Vista. Basically Windows Mobile 2003/5/6/6.1/6.5.
I just got around to putting this on my memory card tonight as i've been using the may 2009 one, checked it over and everything is working fine. I've listed the download links below. This is really useful if you don't have an unlimited data plan to have the whole thing offline i'm using it on a Dell Axim X51v. Thought this might be useful to some people so i'm posting it here as a freebie as its very useful to me.
Credits: sh0dan created the MDX Wikiparser 1.1 & HardDrive used the parser to convert the latest dump to .mdx.
MODS: Wikipedia is freely available to all and dumps the files on their own website for free download by anyone. Those files are raw data and need to be converted and I have given credit to the converter above. Mdict is a freeware program available at the site listed above.