How to Freeze  Beans:

Sort and snip ends.  Wash.  Leave whole, cut into uniform lengths or slice lengthwise into strips for french style.  Cut italian beans into 1 -1/2 inch lengths. Blanch for 3 minutes, cool immediately in cold water; drain and package into containers. 

How to Freeze Beans – Unblanched:

Snap off ends of beans and snip or break into desired lengths.  Wash and allow to dry completely.  When beans are dry, put into freezer bags or boxes.  Beans will keep approximately 6 months with this process.

From the Practical Produce Cookbook