Currently I’m using Pencil, its a good Mock up software and its free. Does anyone recommend me good (free or commercial) mock up software for web design other than Pencil?
I find that browsers are great for mockups. 
And they’re free. 
Thank you for the effort finding this article sir…
You’re welcome. I know it didn’t really answer your question, but I thought it was worth adding to the mix.
I quite like balsamiq. The sketch style helps communicate that this is a mockup/prototype rather than a full design work in progress so the end client focuses on the initial task of refining structure and layout rather than getting drawn into concentrating on design minutiae prematurely.
Many of my clients like Balsamiq for the reasons EastCoast mentioned. Personally, I prefer a simple pencil and paper to do rough sketches, then translate these with HTML and a bit of CSS.
If you prefer digital software, then this article has a quite a comprehensive list.
I just went through the process of reviewing these and I thought 3 stood out for my purposes. Note that I did not want to pay a monthly fee. I am a single wannabe designer / developer that is just getting started, so keeping expenses down is quite important. The 3 that I really thought stood out were Balsamiq, Wireframe Sketcher, and Iplotz. All have trials and are quite approachable and easy to use. I don’t really think you can go too far wrong with any of them.
Note that my least favorite of these 3 was Balsamiq. The monthly version includes a multi-page project feature, but the standalone version does not. This was a bit of a deal breaker for me even though overall it was probably the best product. Lack of a single feature knocked it down for me.
thanks a lot for your help. I’m trying out those tools right now.