Can I mod my phone with bootloader locked? I have a Motorola Defy ('jordan') that I have just recently rooted. I would like to add a mod to it though as it is running on Android froyo still but my bootloader is locked so i'm not very sure how to go about this. Any help would be greatly appreciated.
Even if the Defy's bootloader is locked, you can still root it and install custom roms. It's with the help of a software called 2ndInit.

As mentioned in the comment, you can search in the xda forums to get the details. You can start here by rooting and then install any custom rom. :)