While the iPhone 4 seems to boast 802.11n Wi-Fi, it unfortunately does not support the 5GHz frequency band, according to TUAW.
I asked Glenn about this on Twitter, and he confirmed my fears that 802.11n in 2.4Ghz will suffer from the same interference that b/g devices do. This makes "802.11n" partly just a marketing bullet point for iPhone 4 instead of a truly beneficial feature. If you're currently running a 5GHz-only N network, your iPhone won't take advantage.
I asked Glenn about this on Twitter, and he confirmed my fears that 802.11n in 2.4Ghz will suffer from the same interference that b/g devices do. This makes "802.11n" partly just a marketing bullet point for iPhone 4 instead of a truly beneficial feature. If you're currently running a 5GHz-only N network, your iPhone won't take advantage.