I assume by "locked" you mean to say that you're missing the key (as opposed to the cap is stuck by way of rust, or something like that).
Look as the tools in Glens's post - this is spot on. If you have a bit of time, consider getting a small set from Southord; this is where I get all my stuff (that I don't make myself) - the quality is top-notch. If you just want to get this think opened fast I would recommend the following techniques:
1 - Bumping. To make a "bump" key though, you'll need to know what type of blank the lock uses.
2 - Jigglers. Google "lock jigglers" or something to that effect. You'll still need to know the general shape of the blank, but the precise fit is far less important as long as you can touch all the pins, like this Jiggler.
Worst case scenario, you do it by hand.
Use a small pick, bobby pin, etc. - anything that will allow you to "feel" the pins will work. Directly above (or below, depending on angle) you will apply slight turning pressure via the "tension tool" (flat metal bent into an "L" shape). A complete noob should still be able to tackle this in about 30 mins (30 secs if you're lucky, or experienced). And yes, you do run the risk of damaging the locking mechanism if you don't know what your doing, but that will just make it easier to pick in the future (usually).
Hope this helps. Mechanical picking is actually pretty fun. (edited)