Certificate Manager does not require administrator access.
When you manage your personal certificates in Windows, the tool to use is Certificate Manager - you can access it either by running "certmgr.msc" to access your own personal certificate store, or by running MMC, the Microsoft Management Console, and choosing File | Add / Remove Snap-in to add the Certificates snap-in. You'll then need to choose whether you're going to access your personal certificate store, or the local computer store, or the store for a service. As you can see from that description, running "certmgr.msc" is the easiest way to get to your personal certificate store.
In Windows Vista, things are pretty much the same - there is still no direct "user interface" way to open your certificate store (that I am aware of - let me know if you've found one).
One thing that is different is that everywhere the Windows Help and Support Center mentions the Certificate Manager, it takes pains to assure you that you can't do this unless you log on as an administrator.
As you can imagine, since every user is allowed to have his or her very own personal certificate store, entirely at his or her whim to control, Certificate Manager must be able to do everything from a restricted user account - the only thing that cannot be done from a restricted user account is to access certificate stores belonging to other user accounts.
Windows Vista is new - some of its help is clearly going to be expanded on and expounded later - for right now, if you can, it's worth enabling the "Online Help" to pick up changes to topics as soon as they get made.