The Windows program Collocate 1.0 is available for download at michaelbarlow.com. The software extracts collocations in various ways (including n-grams) and provides scores based on MI, t-score and Log Likelihood. This version of the software is now free.
If you want to simply check out the functionality of the software, or have misplaced your manual, you can get it from
Collocate 2.1 is available at modest cost at (http://athel.com/product_