How to unlock all wepons?

There is no way to get all the weapons unlocked. You have to either purchase the weapons with points or credits. Points are awarded for logging in. If you log in every day you get points bonuses and you get more and more points each day you log in. Credits require real money to be purchased. You can pay money in a variety of ways, or if you are too cheap to spend real money you can click the "Free Credits" button on the top right of the Uberstrike homepage: http://uberstrike.cmune.com/ I can't link you directly to the free credits page as it will show my cmid number and my personal offers page. You will have to go to the site and log in then start doing offers. Offers range from surveys to cell phone offers to application download offers. Remember to read each of the requirements of the offer carefully, and do not do the cell phone offers if you don't want to sign up for a $10 per month subscription. CMUNE has a deal with an offers company so they are not responsible for any personal loss you may suffer when doing offers, so be careful.
One last thing: Once you reach level 30 a lot of the weapons that require credits will be unlocked to be purchased for points. Beside each weapon or item there will be a little picture of a lock with a number in it, that number is the level required to unlock the weapon for points
Hope that helps
Carlos