How do I change the Wi-Fi hotspot channel? Is it possibe to change the channel my phone broadcasts its Wi-Fi hotspot on? 

Right now it's using the same channel as my neighbour (6). My router is reporting several unused slots.
If you're referring to the one built into Froyo (and I assume Gingerbread), when you're creating your hostspot hit the Menu button and you'll see Advanced options. In there you can select the channel.