How Does Early Ordering Work?

[diadactic.livejournal.com]

So, I got a gift card for the holidays, to amazon.com, and I notice that Conspiracy is available for pre-order and is about four dollars cheaper than the list price. I am wondering if this means that the price will go up if I order it in March or later. Anybody know how that works?
Also, if I did preorder it, would that mean that it would get shipped to me on March 23, and would arrive, say March 27? So, if I bought it in person at Borders I could get it on March 23, but from amazon would take longer? I talked to the Borders person who said that when stuff is supposed to be released on a certain day, they have in the backroom before that and just put it out for sale on the release day....

So, if I want to read the book as early as possible, do I need to buy it from a local bookstore?

And is it generally cheaper to pre-order books?