Breeding

00dyel

Is there anywhere that you can search for horses from the same sire or dam?

ArmaniJeanss

Try the bloodstock Tab on the Racing Post website. You have to register but I think its free.
http://www.racingpost.co.uk/news/home.sd

Alternatively try the stallionbook website which is ran by Weatherbys who maintain the studbook - though it looks as if the link will only allow you to search by stallion, not dam.
http://www.stallionbook.co.uk/pages/index.html

kincsem

Do you want -
1. Horses by a sire
2. Offspring of a dam
3. Horses by the same sire and dam (full siblings)

If this is just a once off put up the names, and I will see if I can help.

If you want the offspring of a sire like Sadler's Wells the list would be thousands, and many would not be named / never see a racecourse.

You will get the offspring of dams in the General Stud Book (covers Britain and Ireland). It is an expensive set of books ~ €300. The latest is Volume 45 covering 2001-2004 printed in 2006. And of course volumes 1 to 44 cover from about 1700 to 2000. The dams are listed in alphabetic order, and under each dam is listed the offspring she had in those four years, and the sire of each. Many of the offspring are not named, but will be in later editions. At the back of the GSB the sires are listed, and the mares they covered in the four years.
Each country has its own stud book (American, French, German etc)