apologies it's been so long since you posted, i've been away.
with this you've done 2 out of the 3 things i always meant to go back and do to my code.
ie, get the acknowledge pin working and tidy up the code and put everything in easy to include functions.
do you mind if i edit the original tutorial to link to your post @ Trossen?
pointless people hacking away with my code when you've already completed the job.
the 3rd thing i always intended to do with this was use the hardware SPI module instead of bit-banging.
i failed when i tried this before but i've a better understanding of the SPI module in AVRs now.
i'll get round to that one day.