MySQL select records with changes in field

I have a table that I need to select only the records where a field value is different to the value in the previous record.

Example

ID TestField
1 0
2 0
3 1
4 1
5 2
6 2
7 1
8 0

Records 1,3,5,7,8 would be retrieved.

Any help would be much appreciated
Thanks
Stew

 

Select all rows and loop through them with PHP (or whatever language you use).