They are now available. I picked mine up from Roberts Camera this morning.
#2. "RE: EN-EL18a Batteries" | In response to Reply # 0LeeSyl Nikonian since 05th May 2011Thu 24-Apr-14 04:23 PM | edited Thu 24-Apr-14 11:19 PM by LeeSyl
Available from B&H as of today.
Note: It looks like the supply of these batteries is very limited at this point. I just noticed that B&H again has them on backorder.
My order earlier stands and so I am lucky that I ordered promptly after receiving the in stock notification from them.
Visit my Nikonians gallery.
#3. "RE: EN-EL18a Batteries" | In response to Reply # 2