I have a sequential collection of points in X,Y and I'd like to "trace" these into a set of bezier curves. Could any open source bitmap to vector tracing algorithm or library be used for this?
This depends on what you want to accomplish. If you want to see the 'best fit' curve, or at least a rough approximation, you should use a b_spline. A b_spline will fit itself 'inside' the points it is given. For going through the points in question I would generally use a Catmull-Rom spline which, when given points 1,2,3 will pass through point 2 with slope equal to the slope between points 1 & 3.
Sample Code: http://willperone.net/Code/spline.php
Explanation of the algorithm: http://steve.hollasch.net/cgindex/curves/catmull-rom.html