Hey,

I'm no expert but it seems to look like a Neomarica. I just saw today for the first time a picture of a similar flower at the blog of the american iris society.

Here is a link that might be useful: Neomarica

Nice. A free neomarica caerulea. Your iris will make new irises is you let the flowers touch the soil. They are called 'walking irises' or 'apostle plant' sometimes. The flowers get heavy and fall to the ground, then they send out roots. Once they are established, you can cut the rooted plant off of the parent and you have a perfect copy.
Renee

Thanks very much for identifying the iris for me guys,much appreciated.