Thanks to GBHIL at Android Central Forums:
I'll assume you're running windows.
1. DL the Android SDK here -->
Android SDK | Android Developers
2. Unzip the SDK to c:/
3. Download
http://zenthought.org/system/files/a...20091107-2.apk and save it to your desktop as a .zip file
4. Open flashrec and in the assets/raw/ folder copy asroot2 to the C:\android-sdk-windows-1.6_r1\tools directory.
5. Open the command line and browse to C:\android-sdk-windows-1.6_r1\tools (on Vista or Win 7 just shift+right click on the tools dir in explorer and open command window here)
6. Type the following EXACTLY as written:
From the cmd prompt in the SDK/Tools directory:
adb push asroot2 /data/local/
adb shell chmod 0755 /data/local/asroot2
adb shell
/data/local/asroot2 /system/bin/sh
you will see a friendly message telling you to enjoy your root. Notice the root prompt.
7. Now type:
mount -o remount,rw -t yaffs2 /dev/block/mtdblock3 /system
cd /system/bin
cat sh > su
chmod 4755 su
this changes the permissions of su so you call call it and run apps as root.
8. In the Market, download a terminal. I recommend Terminal Emulator. Open it, click and hold menu until OSK comes up. Type in su, and see if $ changes to #. If so, congrats. You're root. Close the term app. If not, you did something wrong. Start over.
9. DL
Downloads - android-wifi-tether - Project Hosting on Google Code on your phone.
10. Open the downloads folder, run the wifi-tether.apk (using your preferred installer). Once installed you're done. Run it, surf away. Be prepared for a big bill should you do something silly and get Sprint's attention, unless you have PAM on your account.
protip - dl and install google chrome on your computer to use while tethered. Shows a google footprint instead of an IE/Safari or firefox footprint, and wont raise as many flags to Sprint.
Thanks to his info, I got a good Nandroid backup, cache to sd and wifi tethering.