Toe = The amount the wheel is pointed in or out. Known as "In Or Out Toe" Pretend your looking down at your car from above. Looking at the front tires, if you had a Toe In you would have a V shape. The Front edges of the tire are more out. The rear edges more in. (Going towards the front of the car). This affects turning and your turn radious.
Camber= The Degree at which wheel sits. It is in relative to the road. A 0 Degree Camber would mean its flush with road. Most cars have .5 Degree Camber (because roads aren't flat due to water drainaige). When you lower a car the control arms (eventually) connect to the tire, and because you have lowered the car the control arms make the tire (generally the top) move in towards the car. This causes the car to run on the inside of the tire, which wears the tire down much quicker. By replacing the camber you can adjust this camber amount and "push" the tire to lesser degree. (all generic terms due to all cars ahve different suspensions)
The reason Toe is created on certain cars that are lowerd is because of the way the suspension system works. If there is any angle in the control arms the tires would toe in/out. However, you should not be running on a large degree of negative camber, therfore when you align the wheels the toe return to the way it was originaly.
Lowering tire pressure causes more of the tire surface area to touch the road, allowing heat to be distributed more evenly. However, this will not fix a negative camber of more then a few half degrees. (Keep in mind running high pressure will cause the opposite effect as well)