That is correct......4X108, you can trust EVERYTHING in the "newbie" forum. Tirerack.com will show what the wheels will look like on the Focus, Speedandstyle.com has some really good prices on packages, but their customer service sucks ass. I'm sure there's tons of other places to look for wheels at a good price.
Point of clarification (I was a little confused on how the numbers were being translated):
108mm = 4.25 in. (pretty much Ford specific as mentioned)
100mm = 3.94 in. (what most call a 4.00 inch bolt pattern and agreeably probably the most common 4 bolt pattern)
114.3mm= 4.5 inches (found in some 4 bolt patterns but is a common five bolt pattern)