Seen someone ask about this in the shoutbox, so figured I'd post a link. Use this calculator to convert your suspension spring rate between metric (kg/mm) and US (lb/in).
http://www.dfaulknersprings.com/convert.htm
Also here is a cheat sheet for a quick reference:
kg/mm to lbs/in
-----------------------------
16 = 896
15 = 840
14 = 784
13 = 728
12 = 672
11 = 616
10 = 560
9.0 = 504
8.5 = 476
8.0 = 448
7.5 = 420
7.0 = 392
6.5 = 364
6.0 = 336
5.5 = 308
5.0 = 280
4.5 = 252
4.0 = 224
3.0 = 168
2.0 = 112