Nintendo's best handheld console to date! (in my opinion)

I just got this console for christmas, with 2 games and a case to go with it. The Nintendo DS lite is an update of the original DS- it plays all the same games etc. but the screen is brighter than the original DS, it is smaller, and the brightness can be adjusted between 4 different levels (the older one simply had a backlight on/off option). 
I never had an original DS so I can't really say how much of an improvement this version is over the older one-I just know there was some kind of improvement from reading about it on the internet.
The console actually has 2 screens-one of which, the bottom one, is a touch screen, which can be used with a stylus or your finger-but of course if you use your finger you'll get the screen pretty dirty :). The system opens and closes, with the touch screen being on the "bottom" half with all the buttons, and the batteries, and the "normal" screen being on the "top" half with 2 speakers on either side of the screen. With the exception of the touch screen, the controls are MOSTLY the same as the GBA- one D-pad on the left side, shoulder buttons, and on the right side, start and select and A and B buttons-but also X and Y buttons adjacent to those. The stylus has a very blunt, rounded tip, presumably to reduce the likelihood of the screen being scratched by over-enthusiastic players. The system actually comes with 2 styluses, in case you lose it. There is a slot to store the pen when not in use, like a palm-pilot or most other things that have a stylus. the power switch is on the right side, right near the pen slot. There is a head phone jack on the bottom, and a volume slider near the jack. 
The top cover part is red, but the rest of the system is black. The games are small cards, comparable in size to an SD card-but not actually SD cards, these are DS-specific cards. The system can also play GBA games, but doesnt work with GBA link cables, or game boy color/original game boy games. 
So far, I really like this console. It's compact, and will fit right in your pocket. I tend to carry mine in a little "trapper-keeper" that I got with it, which also holds my games. I got super mario 64 and animal crossing: wild world. Look for reviews on these games soon!

Each game "spreads out" across the 2 screens differently. As mentioned previously, some games use one screen for the "action" and the other as some kind of status screen. 

The touch screen control tends to work well most of the time- In super mario 64, you can reconfigure to just use the control pad if you want to, or use the stylus and use either the control pad or the A, B, X and Y buttons. To move your character, you generally have the choice of either using the D-pad, or moving the stylus on the track-pad, where the further to each side of the screen you go, the faster you move. So, if the game requires you to "sneak" you could either "tap" the D-pad instead of holding it up, or you could move the stylus just a little bit away from the middle, kind of like using an analog joystick on a home console. I am right handed, and using the stylus as movement control, and setting the game up to use the D-pad and/or the left shoulder button to attack, jump, etc. feels the most natural, and your milage may vary. Some games may just use the top screen for aesthetics-animal crossing for the most part just shows the sky, and when you're in a building, not in an inventory screen, the top screen shuts off completely. The graphics aren't that great by today's standards, around that of the N64, but the system has better battery life as a result, so it's a win for me.

This console excels in the portability department, not only because it's small/compact, but because of the somewhat durable game cartridges, the bright screens, and long battery life. The batteries are rechargeable, and they are charged like a cell phone-you just plug in the DS to charge the batteries. When the batteries are low, the green power light turns red, but even at this point you've got enough juice to play for a few hours longer. I've played it for long periods of time over the course of the day, and I generally plug it in at night when I go to bed. The brightness can be changed, but it can only be changed in the main menu, via a little touch-screen icon, before you start the game. That's probably my only real complaint with the system- an actual button or knob would have been nice. 

The DS has wi-fi abilities, which can either connect to the internet with a wireless router, or connect to a nearby system directly. The DS can only access networks with WEP security- you'll have to reconfigure your router if it uses another kind of security other than WEP. also, it cant be set to "G-only"
 Playing multiplayer over Wi-Fi is somewhat limited in some games, due to nintendo's "friend code" system, which all of their own games use. However, there may be 3rd party games that have no friend code system, instead using a PC-like interface for online gaming. Each game has it's own unique "friend code" which is like a phone number. In order to play with someone, they need your friend code and you need theirs. Some games may allow "random matches" over the if you so choose, but you generally can't send messages in games that support messaging when you do random matches. I generally prefer to use a computer for playing games on the internet anyway, so that's really not a big deal.