I qualify this because I have seen stocks with less than a million share float trade several million shares in a day and not move. This is caused by market makers who can 'naked short'. That is, sell stock they do not really have in order to control price. There is currently not much that you can do about this right now. The powers that be are looking to change this but it will take time so you have to play with the rules you have right now.
Rumors are everywhere.
They are about anything and everything to do with a stock. BUT they will move the price of a stock up or down as fast as any fundamental will move one of the chips. If you are going to daytrade pennies, you will need to spend as much time following the rumor mill as you do looking into the company. Message boards will tell you what is going up and what is going down if you take the time to read them. I am not talking about the hype somebody puts up to try and get the price of their stock up because they got stuck, but the general sentiment.