I think there is only one program to download as a subscriber and that is the Character Builder. All the other programs are accesable through the D&D insider tab under "Bonus Tools". There you will find the Encounter Builder, the Ability Generator, and the Monster Builder. From the tab you can also gain acces to the D&D Compendium which is essentially written stats on every monster, ability, feat, class, item, whatever in the game. And that includes anything from the online magazines which you also now have access to.
The monthly charge is a bit expensive, but everything you get with it certainly makes a player's life easier.