What's the difference between the iTouch 3g and the iTouch 4g?

I'm looking into buying an iTouch, but I'm not sure what the big difference is between the 3g and the 4g. Can anybody help me out?What's the difference between the iTouch 3g and the iTouch 4g?
The 4g ipod touch has a lot more features than the 3g. For example, the 4g ipod touch has pretty much all the features of the iphone 4 except you can't call/text people on it (excluding facetime) and some of the apps aren't available or as useful on the 4g. Also, the 4g ipod touch has two cameras (one on the back and then one on the front for taking pics of yourself or for facetime). Other differences is that the lock/unlock button is on the top of the right side on the 4g and the left side on the 3g, and the 4g ipod has voice control (built in mic and speaker) whereas the 3g doesn't. Another major difference is the size the different generations are available in. The 4g comes in 8gb, 32 gb, and 64gb, and the 3g comes in 8gb, 16gb, and 32 gb I believe.

One last thing to consider is price. Obviously the older generations will be less expensive than the new one, so if you don't really care about the extra features and want to save some money then i'd say get a 3g. But, if you want all the extra features and the option to have more space get the 4g. I currently have the 4g (my 3g got stolen) and its done everything i've asked of it and more. Also, i just remembered that the 4g has an additional accelerometer or gyroscope or something like that that the 3g doesn't, and the screen resolution is sooo much better haha. Hope this helps.

Edit: i just realized you had a second part to your question and the answer is no, the 3g ipod touch doesn't have a camera, which is another reason to get the 4g.What's the difference between the iTouch 3g and the iTouch 4g?
one has a mic built into it which is really nice and the volume buttons are seperated on 4g. 3g is less expensive otherwise the same.What's the difference between the iTouch 3g and the iTouch 4g?
one has an extra g