No, you can't. Most people believe that syncing, folders, etc. will be made available with the Leopard release.
For the meantime, you can use the Address Book workaround that I posted elsewhere. Here it is:
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The "work-around" that I use is pretty easy.
Go to your Address Book (Mac) and create a new group for notes. I have named mine: *Reference Notes, *Current Notes and *Books. (I put an asterisk in front of each to keep them at the top of the Groups lists.)
Create a new contact, click the "Company" checkbox and type the title of your note. Then type or Copy and Paste your text into the note field. That field holds a lot of text. I have copied the notes (about 75 of them) from my Palm. These are things I like to refer to in my work, etc.
The nice thing about this is that you can edit or add notes on your phone. To add to a particular group, just make sure you are in that group and hit the + sign.
I keep books read and books I want to read in the *Books group. Same way: Title in the Company Field, Author in the Name field, everything else in the note field.
I am learning a new langauge and I have created a *Vocab group which holds nearly 400 vocabulary words right now. The beauty of this is that it works like flash cards. I can choose the group on the phone and "flick" through the list. If I can't remember the word, I touch it and the card comes up revealing the answer.
The Address Book is an excellent database for things other than addresses. The down side is that when you want to make a call, you need to choose the group from which to pick your contact (so that you're not scrolling through notes, books, vocabulary words, etc.) but that is not a problem for me. I have all of my contacts in a various groups (Work, Family, Friends, Businesses, etc) and then I have one group which contains ALL of my actual contacts (in case I can't remember what group a person is in).
I have over 1,700 entries in my Address Book and it usually takes only seconds to find what I need.
Until Apple comes up with a better Notes application and/or database, this work well for me and syncs in seconds.