I have just added nearly all the forum users to the wiki. This means that you can now use your forum login to sign in to the wiki! However, not everyone can do this; about 2500 people were not brought over. I'm currently working on moving them over to, but it doesn't want to cooperate there. For reference, there are about 16000 users moved over. Thus, your odds of being unlucky and having a profile that won't move over are quite low.
In order to log in you will use your forum username with the first letter capitalized, if it isn't already. Spaces and other character are there too. Your password for the wiki is whatever password you had set on your forum account as of 7:00 P.M. EST of today (Saturday, March 07, 2015).
If you cannot log-in using those credentials or have any questions, please PM/email me or post here.