The folks over at Androidguys have gotten a pretty reliable source that gives some insight about Samsungs bootloader policy. According to their source Supercurio, Samsung will not used locked bootloaders on their future devices unless Google specifically required them to. Supercurio was also able to give a bit of info regarding if the bootloaders would be unlocked on their tablets:
Tablets projects are still young, I don't know about the bootloader plans for those devices.
What does an unlocked bootloader do for you? Pretty much it allows people to flash custom roms to their devices very easily without all the painful hacking. Androidguys are very to the point that this is still a rumor, but a rumor for a very reliable source. So for all of you that love flashing roms (me included) will now have a little more incentive to buy more Samsung devices.