Finding nodes between other nodes

Hi

I appear to be especially short of tuits today and I'm having trouble 
getting my head round the XPath 2 expression I need to create.

I'm trying to find all processing instructions that occur between the current
node (which will always be a text node in this case) and the next text node
(in document order). 

I know I should be able to do this and that following is involved but my 
intelligence is failing at that point.

Any help will be gratefully received

cheers

nic