If on a mac, follow the dev's page. :P
If on a PC, download 7-Zip from sourceforge.
Download the .tar.bz2 files such as stardict-dictd_www.dict.org_gcide-2.4.2.tar.bz2 also from sourceforge.
Decompress. Once you have 7-Zip you can right click and extract using it, much like with winzip etc.
Keep extracting, takes about four goes to get everything. Remember to extract the .dict.dz file until it is just a .dict file.
Ctrl click the .dict and .idx file and use 7-Zip to zip it.
Upload your .zip file to your homepage server. (or you can try the upload page at the developers site)
Download your zipped file to the ipod using the url for where you put it; if you know how to upload it you know how to download it.
Note: It seems to be very important to use 7-Zip for this. I presume it keeps the file integrity/format the Mac uses. When I tried this using four or five other zip/unzip utilities, it would NOT work. You could uncompress, recompress and even download it but the ipod wouldn't unzip it.
Good luck, gang.
PS, if you're going to upload the raw .dict and .idx files to your file server, be aware that you should RENAME the .dict file once you upload it to your fileserver. Mine attached an invisible .txt tag so the file was actually called .dict.txt but you couldn't see the .txt part. I only found this out when downloading it to the ipod and had a wtf moment when I noticed the additional .txt part. After I renamed the file whatever.dict I could download it to the ipod touch. Your milage may vary.
I must say this is a lot of sweat and bother just to get some dictionaries on the wedict pro. Of all the aps I have or have had on my 1G or 2G this has been the biggest PITA! To be fair, once you have it set up, it's brilliant. I use it all the time.
Edit: Here is a link to SOME working dictionaries re-zipped from sourceforge (not illegal, freely available files just re-zipped to make suitable for iPod or iPhone download.) Note that at least one does not work. Read the comments there before downloading directly to your ipod touch.
IMHO the developer for this app should be hosting these files and save us all a huge blimmin' headache.
If any of you get the community dictionary uploaded, PM me as it was too big to put on my home page server so I can't get it. The one at the link above doesn't work. I'd love to grab yours.