Not all iOS device Wi-Fi speeds are created equal. If your family has a mix of devices, like an iPhone 4S, iPad 2, and iPod touch 3, it can be difficult to get maximum performance from your Wi-Fi router. The iPad can do fast 802.11n on the relatively clear 5GHz frequency. The iPhone 4S can do fast 802.11n, but only on the more cluttered 2.4GHz frequency. The iPod touch can only do slower 802.11b/g, and only on 2.4GHz. Even if you have a dual-band router, like Apple's latest AirPorts, even as the iPad zips along at 802.11n on 5Ghz, the slower iPod touch or even an iPhone 3GS will force the iPhone 4S down to 802.11b/g on 2.4GHz. So what's a geek to do?
If you have a desktop computer or server that stays on most of the time, you can set up Bluetooth tethering for your older devices, getting them off Wi-Fi and letting your 802.11n devices speed along unhindered. It's a bit of a workaround, and your Bluetooth-connected devices will be limited to 20mbs, but the slower slows will also give you faster fasts on your more modern devices. For me, that's a great tradeoff. If you agree, here's how to do it on OS X Mountain Lion.