prelim self employed

My income has fallen and I am hoping to move from an accountant to a website/software type package to do my taxes.
My accountant filed my 2011 accounts.
The software package seems to be straight forward when I will be finalising my 2012 figures but I don’t know the procedure for my 2012
prelim figures. If I go on 100% of last years figures it should be zero.
Will there a form sent to me by revenue or do I have to get it online and is it just simply filled out as zero with no accompanying data?

register on ROS.ie and follow the instructions

Out of curiosity what's the software package?

Your current accountant should've done this as part of the filing of your 2011 accounts (especially if there's no tax due). If in doubt follow J.Ryan's advice - you'll need to register for ROS anyway.