Yes i've had to replace a leaky pump on my 2006 X3 and my aunts 2008 model. It seems this is a very common problem. I created this do it yourself guide to document the process and show how easy it is to order the part and change it yourself:
BMW X3 Washer Fluid Pump Replacement How To
Hope it helps someone else save some money, my dealer quoted me $65 just for the part so i'm sure it would be well over $100 installed. You can get the parts online for about $35 and replacing it is easy.