Hi Michael:
You'r talking about two diferent things! Like Ernest Ford already told you: - "any finacial transactions being done over the internet should be done using an encrypyted channel, whether or not wireless is involved" Witch is why SSL is used.
In this case the data you'r exchanging with your bank is being encrypted, "hackers" can still sniff your data, but will be sniffing encrypted data.
Now what u r talking about microsoft, means that, u can also encrypt the wireless connection, but if you'r using a wireless connection that doesnt bellong to you, like a public one, you are limited to the security of that particular wireless network.
In a wireless network you can configure the authentication type and the encryption type, if the wireless network is using WEP encryption there's a change "hackers" can penetrate the same network, but if the network is using WPA or WPA2, it's not likely, or even impossible that the same network is compromised. So if u want, u can try and make shure that wpa or wpa2 is being used to secure your traffic.
Having a firewall is also a pretty important security feature, so be shure to have your firewall always active.
There's alot to be said about wireless Security, with would be too long for this thread. So in resume, try and make shure of four things
1) you have a firewall;
2) the site you r exchanging confidencial information is a trusted one and is using SSL;
3) Wireless encryption should be WPA or WPA2, WPE is not secure.
4) hope i'm not forgetting something..... ;)
regards,
hugo