If you own an HTC mySlide 3G from T-Mobile you can now get Froyo update. The update is not free-to-air so you need a computer to update this.
Android 2.2.1 FroYo features
• Wi-Fi calling
• Wi-Fi hotspot
• USB Tethering (Internet Sharing)
• Low storage (User Data) notification mechanism
• Resolves issues with text and picture messaging
• Resolves some Bluetooth compatibility issues
• Improves compatibility with new Bluetooth devices
• Improves stability and reliability of the device
• Other various minor bug fixes
Download HTC mySlide 3G Froyo update: here