In reply to malk:
The bar height is only a part of it and in many ways more important with regards to flexibility rather than pure height. Its the top tube length etc and whether you will have your knees round your ankles which will make a big difference.
In terms of sizing guides they tend to be more guess work than anything else. The Ape index for example can mess things up.
Then you have the problem that, just like clothing, sizing seems to be completely bloody random and the use of an actual figure may or may not bear any resemblence to what it actually is.
So, in summary, best thing is to try it and see.