Sprint just announced that starting June 20th they will release an OTA Gingerbread update for the HTC EVO Shift 4G. For the impatient among us, we can go get that update today or tomorrow manually! You just have to go to Menu>Settings>System updates>HTC software Update, which will manually start the update process. Here is the press release from Sprint below,
ANNOUNCEMENT

HTC EVO Shift 4G from Sprint will receive the Android 2.3, Gingerbread, update through an over-the-air maintenance release beginning on Monday, June 20.

Sprint will send update notifications to users in waves. The notification will let users know the update is available and provide the simple two-step, over-the-air download instructions.

Users will receive a notification that Android 2.3 is available for download.
Once the user has downloaded the update, they will be prompted to install the update. The user will be notified that their device will be disabled during the installation process. The phone will be ready to use once the process completes.

For those who just canít wait to get Android 2.3, there will be an easy user initiated option to download the upgrade starting today. To access the update Ė from the home screen/Menu/Settings/System updates/HTC software Update. This will initiate the upgrade process.

The software release upgrades HTC EVO Shift 4G to Android 2.3, Gingerbread. This version of Android improves download management through the Downloads application, offering the user easy access to any file downloaded from the browser, email or another application. It also fixes the devices ability to stream media through certain applications for the device.

It also adds SWYPE text entry capabilities for HTC EVO Shift 4G.
Source: SprintDroids via TalkAndroid and Sprint