In reply to mattrm: Hi Matt, don't bother with the Orkney seastacks site for bouldering as it has none but 2 options.
1. At yesnaby walk right round passed the stack and all the main cliffs and follow the coastal path south to the next headland. It is low and rocky and has some pleasant bouldering in a great setting looking back north to Yesnaby.
2. The Pools of Birsay is a cracking wee spot I discovered this year and has the benefit of being close to the excellent Birsay Tearooms. Pics are here
http://www.flickr.com/photos/8027420@N04/9383586793/ This is the main pic and there are several others in my photostream plus a heap of yesnaby. It is a wee bit snappy as it is so new but essentially very sound. Ideally you want an afternoon and a lowish tide. Head to Birsay and then aim for the cemetery south of the village. Follow the road seaward to a right angled bend where a rough track continues seaward. Go down this path and when you reach the coast the Pools and the extensive area of geos and arches is immediately south. Enjoy
Ps good bouldering wall in the Pickaquoy centre but a pain in the hoop getting in it as you have to be inducted. Try the Orkney climbing Club on facebook and they may be able to help