Chances are if you bought your HTC Hero recently, you're already running the latest firmware.

If you want to get access to root or the Android Market, you can try flashing a custom ROM that has root access.

Step 1: Install Amon Ra recovery image using FlashRec.apk.
Step 2: Choose a custom ROM and flash it. If you want a stable Android 1.5 ROM, get MoDaCo. Villain and a few other ROMs support Android 2.1