Unfortunately, you will not get Android 2.3 for the Sprint HTC Hero automatically through an OTA update from Sprint or HTC. If you want Android 2.3, you will need to root your handset and flash the ROM of it.
Head over to the rooting section of this forum for information about the above. Also, I would wait until the Android 2.3 ROMs become stable enough to use as a daily driver.
Nokia 638 > Motorola Talkabout > Motorola V60t > Motorola V60i > Motorola V505 > Samsung Epix > HTC Hero
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