1) Changing the wireless MAC is no different than changing the LAN MAC. Find the "Properties" section of the wireless adapter and look around until you find the place where you manually set your MAC. I've never found a string of characters that would not be accepted. This is in response to the person that thought that there might be some restrictions on what alphanumeric characters you can use. It's hexidecimal, I think. Like this 3B : 5K : TP, etc... I think you actually CAN put "anything" in there.
2) I'm curious as to why you want to change your MAC. I've experimented around a learned a few things about changing the MAC. First thing I learned is that the MAC is only supposed to be an "internal network only" identifier. It's not supposed to be shared outside of your internal (home, or business) network. I've done some research and have found several articles, and forum posts that say that both Java, and Java Script, and maybe ActiveX can be hacked so that a website you visit will force your machine to violate security protocols and deliver your MAC Address to the website running the hacked malware scripts. One article said this was one method the FBI used (malware) to definitively prove that a particular computer did illegal activity "X".
But browser fingerprinting is a much more reliable and easy way to do the exact same thing.
Think of it this way. If you were on the Jury and the Prosecutor said that the FBI determined there was a 1 in 5 million chance that someone else's computer browser did illegal computer activity "X", would YOU vote for acquittal? My point here is that they don't need the MAC Address to prove it was you. All they have to do is get the record of the browser fingerprint, and have the physical computer in their possession (meaning they've seized it), in order to prove that a particular computer did a specific, presumably illegal computer activity (let's say it was credit card fraud on eBay, to keep things as non-controversial as possible).
My whole point here is that changing your MAC doesn't really afford you any privacy. Malware can hack your MAC Address, but nothing (or very little) masks your browser fingerprint. Except I posted on the Pale Moon Forums once, requesting that the Developers there make what I called a "browser fingerprint rotator" which makes regularly scheduled changes to your browser's fingerprint (every "x" minutes, or every "y" page loads) so that your computer never presents the exact same fingerprint to a website. A few weeks, months later there was an announced change in Pale Moon, but I never found out if my browser fingerprint rotator idea went anywhere.
Point is, again, if you want privacy, you need to worry about malware and hacks, and also browser fingerprints. I don't think the MAC Address is going to do much for you. But I could be wrong and that's why I'm posting all this. Maybe I'm wrong and there is something for me to learn here.
Another thought I had was MAC spoofing, which I've thought about, but have never done. That's where you copy the MAC address of another device and the computer network accepts it (your spoofed device) as being the "original". My home network has a "whitelist" of MAC Addresses and if the device's MAC Address isn't on the white list, it's not allowed to connect to the network. I mention this because IMO this is a minimum basic measure of network security that any layperson can learn to do in an hour or so. Find the "white list" section of your cable modem, router, or whatever, and restrict access to your network to only those devices that have MAC Addresses that are on the white list. Keeps your neighbors from connecting to your wireless network in order to sniff packets or brute force/dictionary hack your wireless passwords. Also slows law enforcement down a bit and gives them an extra 10 minutes or so of work to do in case they also would like to join your network.
Again my point is that you aren't keeping them out, if that's your intent. IMO the biggest security hole there is is the false sense of security the uninformed User has.