Here's a place that will send you a free sim card ahead of time. It's a UK phone number, but works perfectly in the Netherlands. You give them a credit card and simply pay for what you use. No commitment. No annual fee. No expiration.
I think their rates (for the above benefits) are rather reasonable, especially if you want to use the phone for basic "keepting in touch" activities. Their rates in the Netherlands are:
Incoming calls: $1.25/min
National calls: $1.25/min
Calls to the USA & Canada: $1.50/min
Calls to the UK: $1.50/min
Calls to other countries: $2.95/min
SMS text messages: $0.80/message
I got one from them last year for my travels and highly recommend them. They've also been written up in a number of travel publications, as you can read on the site.
http://www.mobalrental.com/gsm/sim.asp
Hope this helps.
- Auston