If you know what you're doing, the process is easy to follow although there is one major drawback. Despite HTC's role in allowing you to unlock the bootloader, doing so will void the warranty on your phone in some situations. If you are not 100% sure that you understand the risks and the procedure involved, you might be better off leaving you smartphone exactly as is.
To begin the unlocking process, head over to the sourcelink where next to the warnings you will find a button that says "Begin Unlock Bootloader". From that point on, you will follow the directions which will take you on the journey seen in the diagram below. Once you are done, you have opened up your HTC phone to a new world of personalization.
If you are an owner of the HTC EVO 4G or the T-Mobile myTouch 4G Slide and you have unlocked the bootloader on either device, let us know how it's working out for you by dropping us a comment in the box below!
source: HTC via AndroidCentral
Owners of the HTC EVO 4G and the T-Mobile myTouch 4G Slide can now unlock the bootloader on each device