You can drag the marker around to lookup as well.
Postal Code Lookup is a little single function site I came up with to scratch my own itch.
I was generally dissatisfied with Canada Post's site - isn't quick enough when I need to look up a postal code.
I was pretty sure with geocoding could just feed in an address and get back the Postal Code. So here it is.
Works pretty well with anywhere that has a Postal/Zip Codes. The UK has certain restrictions, which is why Postal Code info from that region will be incomplete.