Page Changed: The Truth about Oral Diabetes Drugs
Added citation to new study which suggests that metformin stops the liver from dumping glucose by directly stimulating a gene in the liver which should be stimulated by insulin but in many Type 2s apparently isn't. This suggests that it isn't lowering insulin resistance so much as doing the job itself insulin isn't doing.
Metformin and Insulin Suppress Hepatic Gluconeogenesis through Phosphorylation of CREB Binding Protein Ling He et al,, Cell Volume 137, Issue 4, 635-646, 15 May 2009. doi:10.1016/j.cell.2009.03.016
This is explained in layman's language in this week's release of Diabetes in Control:
New Information on how Metformin works. Diabetes in Control May 27, 2009.