For Presentation Remote to work, you'll need a small helper application, Presentation Manager, running on your Macintosh. Presentation Manager is how you give permission to iPhone or iPod touch devices to control your presentations.
Presentation Manager also includes a Wireless Signal Tester, to check the approximate speed and quality of your network.
This is completely free, and you can download it here:
Presentation Manager requires Mac OS X 10.5 ("Leopard"), 10.6 ("Snow Leopard") or 10.7 ("Lion").
“A great tool for those who use Keynote often” — Forbes
“The clear winner — it’s miles ahead of Keynote Remote’s limited features” — Macworld
“This handy application will have you looking like Steve Jobs himself” — AllBusiness
“If you use Apple's Keynote presentation program [...] the perfect companion” — Mobile Gear Reviews
“Don’t faff about with PowerPoint, conduct powerful presentations from the palm of your hand” — ElectricPig