these are the formulas I know:
B=F/IL
F=BIL sin @
B=kI/r
B=2(pi)knI
Where k is Amperes constant (2x10^-7NA^-2), L is the length of wire, I is the current, r is the radius of the wire (but in some cases the distance between wires), and F is the force.
Here's another diagram with...