Navy, Marines, Army and Air Force's learning sites are linked off on the CG Learning Portal. I have a Navy Knowledge Online (NKO) account primarily for use of the e-TA system. But, I'm able to use the other resources too. You may need to have a CAC reader and card to verify credential, can't remember.
If you're using a CG workstation (on shore) shouldn't have to worry about it.
I found most of the computer based training on the Navy's site to be the the same a the SkillSoft training we have available through the CG Learning Portal.
