Sorry I should have been clearer there.
A lot of domain registrars have a condition that a domain cannot be transferred away to another registrar until 60 days have elapsed. I think it is an anti-fraud measure to make sure domains are not purchased with stolen credit cards and then moved away immediately. The 60 days allows for funds to be moved and accounted for…or not.
After 60 days you can transfer to another registrar by completing the appropriate transfer form at that registrar. The other registrar will email DreamHost of the transfer and if DreamHost make no acknowledgement in 5-7 days the transfer takes place.
The registrar-lock is just a safety mechanism to avoid your domain being taken by unauthorised persons. When you wish to transfer you would just notify DreamHost and ask for the lock to be switched off. Once transferred you ask for your new registrar to lock it again, if you so wish.