Need an XL Algorithm example could anyone give me a small example with actual numbers and variables over a finite field of how the XL algorithm is used to solve overdetermined systems? And the steps involved. I understand the algorithm but a simple example would make my life a lot easier. Also are there any implementations of the XL algorithm available? 

Thanks.
I recommend to read book "Algebraic Cryptanalysis Book by Gregory Bard". it has a simple example of XL algorithm chapter 12 page 213 (12.4 The XL Algorithm). 

after that you can develop sage/magma code for capturing the concept very well.