iDictionary is a Mac OS X application that allows you to create a custom dictionary and/or thesaurus for your iPod, and easily put it on your iPod. iDictionary leverages the built in dictionary available with OS X 10.4 along with some very smart filtering and optimization techniques to create a dictionary or thesaurus that will fit on an iPod. Although the dictionary/thesaurus is optimized to fit on your iPod it is still a fully featured dictionary containing most of the words (maybe more) a normal dictionary would have. Download iDictionary and try the demo to see for yourself!
Hard work has gone into optimizing the dictionary creation process to use the least amount of space possible since the "Notes" feature of the iPod can only hold 1000 note files, holding a maximum of 4mb of data. iDictionary has an array of options available that allows you to customize your dictionary to exclude words that match certain criteria to save space, since the iPod can only hold a finite amount of data.
New in verson 1.2 is the ability to choose the file format of your dictionary/thesaurus. You can choose from the iPod Contacts, or iPod Notes format. The Contacts file format has no limit on the amount of files it can display so you can view the whole dictionary and thesaurus without worrying about file limits.