Download a free version of Eureka Email (2.8Mb). There is no 30 day time limit on the free version as with some other email programs.

The standard version of Eureka Email comes with an 80,000 word dictionary. You can download this larger dictionary which is 920Kb and has over 200,000 words. Once you have downloaded the file just unzip it and copy it over your existing dictionary.dat file in the folder that you installed Eureka Email to.