Valyrian Steel, producers of replica swords based on the A Song of Ice and Fire, have posted concept art for Ice. They explain how the design process works—GRRM is the final arbiter of how it should look—and some interesting details are provided about it. However, the sword is not going to be produced for sale sooner than late 2010. A Damascus steel version is also planned.
Valyrian Steel has examples of Longclaw and Needle available for purchase from their on-line store.