For Sony Ericsson XPERIA X8 and X10 users, here is some good news for you all. XDA forum member the_laser found a method to unlock bootloaders for those phones. This method works on all of the SE 2010 phone lineup.

An unlocked bootloader enables you to do things far beyond simply having root access. An unlocked bootloader is required in order to load an entirely new ROM and kernel.

From the developer:

“here is toolset to permanently “unlock” semcboot of qsd8250 semc phones ( x10a,x10i, so-o1b )
that means, you can use own kernel and so on.
it is much more better,stable,faster method, than present “bypass”.

This is pretty cool. Too bad I’m not a user for those two phones.

Source