Thought I'd share this: I've been corresponding with someone who reads my blog. I'm not sure of his background, but I believe he's a tailor. He certainly knows a lot about the trade.
Anyway, we were talking about various shirting issues yesterday and he confirmed that sometimes - depending on who you get your shirting from and where you take it to be made up - you may want to preshrink your fabrics. His instructions:
1: take the cut(not the selvage) ends and sew them up(not together, just sew the raw edge on itself) overlock(merrow) or hand overcast will do, this is to prevent the cloth from fraying in the wash.
2: throw it in the washer, run it as you would normally, cold water etc.
3: tumble dry, high temp is fine, dryer sheet and all.
4: re-true the grain, press it and cut.
Most producers won't bother with this process, but the resulting shirt elevates the lowly PB cloth into something really great. I had problems with the cloth until I started running the goods through a wash cycle.
On high end fabrics, this process is done in finishing. Aluomo as an example only uses water and detergent when finishing their cloth. Effectively preshrinking the goods on the roll(figurative not literal).
Thought it that might be helpful given people's earlier discussions on this topic.