GMail2

It allows you to maintain your own e-mail lists and send personalized messages to your lists. You can add recipients at run time, or just load them from a text file, or both!

GMail2 also has a verification feature which will verify all your e-mail addresses for you, also supports multiple attachments (Registered version only). This is great for sending personalized e-mail messages. This new version has new sorting and duplicate-removal features! You can sort the list and it will automatically remove duplicates to a dupes.txt file for you!