Maybe even more important than your current website -- and here is why:
• Google has confirmed 50 times more searches from the iPhone than from any other mobile handset. Their engineers had to double check the logs when an analysis showed the amount searches coming from iPhones was 50 times higher than others.
• In the UK; O2 recently confirmed the iPhone to be driving "unheard of data traffic" on the mobile network.
• New York Times: 58.6% of iPhone users visited search engines on their phones
• Google has launched a version of iGoogle specifically for the iPhone.
• iPhone is the number 3 most talked about product in the World

If you check the mobile usage statistics above, you'll find that more people use the iPhone for browsing the web than any other device