Instead of saying "the solution to problem X will actually be available TONIGHT at www.[startupname]ly.com" couldn't you say "the solution to problem X will be available SOON/LATER/NEXT YEAR at www.[startupname]ly.com. Pre-register so we can let you know when it is" ? First, you wouldn't be deceiving anyone. Second, wouldn't it be an even better indication of interest if people are willing to wait for the product?