This is a great app. For those who have just rooted your Hero's then you are going to want to DL:
Code
http://code.google.com/p/android-wifi-tether/downloads/list?can=2&q=HTC+Donut
It is for the HTC Dream/Magic/Hero 1.6 (Donut) & 1.5 (Cupcake).
First off it's more updated and made for these, but if you use the one above then you will not be able to type w/o hardware keyboard. Good Luck.
--------- New Post Merged on 10/11/2009 at 03:11:27 --------
Now to add to my above post. It appears for the moment you can make this worrk by using CDMA HERO MoDaCo's Custom ROM, because it's not working with stock system. I'm saying this is permanent, but is what is going on so far. CDMA Android has just been Rooted, so things are in motion. If you try to use it, everything will look great, until someone trys to connect to you and no interent is flowing through. This has been mentioned to the developers, so hopefully we'll hear something soon.