Hi Abbie,
Im in the same situation and pretty much have the same question! Its such a waste of money though isnt it, honest to God after hair and dresses to be buying presents.
Anyway, do you have 1 bridesmaid or many? What is your budget? If you want to get something nice in the way of jewellery but dont want to spend a fortune fortune you could get them something from swaroski (spelling?) I think they have them in BTs, but they do lovely christal pieces.
Alternatively you could get them a spa day somewhere (powerscourt springs) to wind down while you are on honeymoon.
I was bridesmaid recently and I pleaded with the bride not to get me anything but it fell on deaf ears in the end she paid for my accomadation that night in the hotel, I thought that was a nice gift and good for someone who might be a bit fussy about what they wear jewellery wise etc.
That said I only have one bridemaid, my sister, and she's going to be a nightmare to buy for.
hope that helps,
good luck
cas