Robin Hoods Playground

I wanted to know if nintendo DS or DS lite have pre-installed software like an address book, memos, etc? If not can software be purchased to add these features? I have looked at nintendo's website and wikipedia, any help is much appreciated.

ive never looked into it

You'd probably need to mod the ds.

I know of a chip called an R4 which can run homebrew, I'd assume there would be a memo app, calender app etc...

Go on youtube, and search nintendo ds r4 and you'll find loads of videos.