In Snowtape in the devices list, click on the entry for your iPhone and enter the code that is displayed in SnowRemote. 
SnowRemote will jump out of the passcode screen and adds a new entry for your Snowtape application to the "Remotes" screen.
Note: Please make sure SnowRemote and Snowtape are connected to the same wireless network. Alternatively you can create an Ad-Hoc wireless network in Mac OS X and connect your iPhone or iPod touch to this network.