Apple’s new OS, Snow Leopard, goes on sale Friday and can be pre-ordered online starting today.It’s a pretty inexpensive upgrade – $29 for folks who work on OS X 10.5 Leopard. Snow Leopard, OS X 10.6, is said to refine “90 percent of the more than 1,000 projects that make up Mac OS X.The main refinements, according to Apple, appear to be in the speed department. Mail is supposed to load up to twice as fast, Time Machine to to its initial backup up to 80 percent faster, and a 64-bit version of Safari 4 that’s