802.11n WiFi driver for BCM4329 chip?

Froyo has it, Nexus one users who updated to froyo already enjoy N although some say the difference in speed is very minimal.

if you are anywhere near your router, wireless g is tons faster than your router-net connection will be, most likely. so, going faster to the router isn't going to make much difference if it bottlenecks at the router.

where you may see increases would be in a WLAN, if everything is configured to N-band. otherwise, if you are accessing a 802.11g device on your network, that's the slow man in your transmission, and it won't matter, again.

What about range (which is a problem for the EVO)

It may only be that the router is better, or it may be that 5GHz is better (I know the new iphone only does N on 2.4Ghz, I'm not sure about the EVO) but I know with my airport extreme the range is better to my MacBook, and that in general other N routers have better range to N devices.

This should answer your questions:

BCM4329 - Low-Power 802.11n with Bluetooth® 2.1 + EDR and FM (Tx and Rx)

The Broadcom BCM4329 integrates a complete IEEE 802.11 a/b/g/n system (MAC/baseband/radio) with Bluetooth® 2.1 + EDR (Enhanced Data Rate), and FM radio receiver and transmitter. In addition to bringing greater Wi-Fi throughput and coverage to mobile consumer electronics, the BCM4329 is Broadcom's smallest and lowest cost dual-band 802.11n solution. It features integrated 2.4 GHz and 5 GHz WLAN CMOS power amplifiers, which reduce BoM costs while maintaining superior performance. The BCM4329 also utilizes advanced design techniques and process technologies to reduce active and idle power consumption and extend battery life.

With wifi-N working, you will get the benefits of dual band.