I use the stadium rules that Neo made, but they are slightly altered. I havn't got them to hand but I'll upload them and post a link to them for you.
The boards themselves are made from insulation foam out of B&Q, £10 a pack which has 8 boards. Crazily enough the boards are 450mm wide, the exact width of the BB pitch (dum de dum dum) so all you need do is trim some bits off the end.
Actually I've just found them! Go to the old website here:
http://www.fragalot.com/old/download.htm and download the 'NBBL Extra Rules'. The stadium rules are in there.
I will get a 'how to' up on the pitches after Xmas.
Enjoy!