Summarize:

Many new features were added with the release of this DS.      You don't have to have the pack now to have Internet. Nintendo has replaced that feature with the option to buy games from the DSi shop using points.
The DSi is the third DS console to be made by Nintendo. This price of this DSi is 99.99, but it may differ online. The model is thinner and lighter than the previous DS models. The main screen is set up similar to the Wii home menu with box panels shown on the touch screen and pictures that you have chosen to show on the main screen at the top. You can take pictures, play around with sounds that you recorded using the microphone,  buy games using DSi Points and use Flipnote Studio. DS Download Play and PictoChat are still on this model. You now have an Internet browser, downloadable free of charge from the Nintendo DSi shop on this DS. You cannot play GBA games on this DSi. In PictoChat, you can now also draw in rainbow colors besides black.