Puzzle of the week #26

Chess Diagram: 


Will continue posting interesting puzzles during this summer under the same setup:
1. One puzzle a week
2. A new puzzle plus the solution for the previous one will be posted each Thursday night
3. Solutions can be sent to me using "Contact us" or be posted here directly as comments
4. If you are a registered member on the website, your comments will appear right away. If you are not a registered member, I need to approve your comments before they appear. Registration is free and easy!
5. Anyone can and is encouraged to participate
6. Will keep track of the points accumulated by everyone and possibly will have a similar prize package for top 3 in September.

Let's get going with a very interesting position from a game between GMs Shirov - Svidler, Aerosvit Foros Tournament, Ukraine 2008. After 24... b5 we reached the following position (see diagram). Questions:
a) Please assess this position for both White and Black; decide who is better (5 points)
b) Propose a possible line (6-10 moves) to prove your decision (5 points)
Total available points for this puzzle is 10. The answers will be published next week together with puzzle #27.


Storming the castle