How to Install Android 2.3 Gingerbread on HTC Legend
1. First of all, you need to download an Android 2.3 Gingerbread ROM for the HTC Legend. Though it's still experimental and has a few bugs, the Cyanogen Mod 7 ROM (Android 2.3 for HTC Legend) is probably your best option.
Download the Android 2.3 Gingerbread ROM for HTC Legend here.
2. Copy the ROM to the root of your SD card and insert it into your device. You can do it by either connecting your phone to your PC or by using a card reader.
3. Now, you need to get ROM Manager. It's an excellent app which allows you to install, back up and restore ROMs easily. You need root access to your HTC Legend to use it, so make sure that your phone is rooted.
Go to the Android Market and search for ROM Manager. Download the ClockworkMod ROM Manager and install it.
4. Open the ROM Manager app and select the Flash Clockwork Mod Recovery option to install the recovery ROM and then select the Backup Current ROM option to backup your current ROM in case you want to revert back to it.
5. Now go back to the main menu of ROM Manager and click on Install ROM from SD Card. Select the ROM you downloaded on the SD Card and install it. Make sure you wipe data and cache before installing.
Android 2.3 Gingerbread ROM Source: XDA
If you have any issues with the ROM, post a comment here or on the XDA thread.
Note: You need a rooted HTC Legend to flash ROMs.