I use a Zire but it wasn't until I got it home that I found that it doesn't include a database program. However I realised that I could use the address book because most of the field names aren't displayed when looking at any of the entries, only when editing. And so I use the fields that are available to hold not just the DVD title but all the extra info that I want (e.g. cast, director, dvd extras ...)
By using the surname field to hold the title, then all entries are automatically displayed in alphabetical order, plus I can search for information held within the records (e.g. film genre) and the search results are also in alphabetical order.