Simon Judge has released a free Webster’s Dictionary 2.0 software for Nokia S60 3rd Edition devices like Nokia E70,N73,N80,N91 and N93. It is a native Symbian 9.1 application (SIS- not Java J2ME based), occupies 6Mb of storage space and can be installed on a storage card

Some features are:

Built-in indexes find words in a fraction of a second.
Includes parts of speech (noun, verb etc).