ive just had a look and the software i have is 3.4 where do i find the link to upgrade it for there website ?
Have a look here, there are links to Canon downloads and some helpful comments, but I think you may find that the version you already have includes support for your kit lens. The major change with later versions is support for new cameras like the 50D and 5D2, plus a load more lenses.
http://photography-on-the.net/forum/showthread.php?t=601380
I've never downloaded it myself. I just bought a new copy of the latest software from Robert Scott Associates who handle this stuff for Canon UK
http://www.instructionbooks.co.uk/ For £12 I got a complete suite of CDs and manuals for a 50D, including DPP v3.5. I also got a subscription to EOS Mag for £8 I think. The package for the 5D2 includes DPP v3.5.1, I believe.
If you want to play around with it with your kit lens, shoot at max wide angle, and at max aperture (lowest f/number). This is where the lens performance is weakest. Shoot a subject like a building with straight lines near the edges of the frame (to show distortion) and with areas of light or mid tone going right to the corners - grass or sky maybe (to show vignetting). Then try and include some fine detail towards the corners, preferably with high light/dark contrast such at branches against the sky (to show chromatic aberration). Edit: worst distortion and vignetting on the kit lens are at close focusing distance.
DPP only works on Raw files of course, but when I ran a similar pic through the lens corrections section the improvement was quite astonishing. Made me wonder why I ditched my EF-S 17-85mm in favour of the much more expensive EF-S 17-55mm

Too late now. I've ditched those files now so I can't post. Sorry.
Don't forget to include your normal Raw processing parameters to the image. If you don't normally shoot Raw, the camera will automatically import the Pictures Styles pre-sets, but you can always overwrite them.
Edit: Check these links

From DPReview's excellent lens tests, a demonstration of Canon's DPP lens aberration correction software at work on the EF-S 18-55mm IS kit lens. It's free, takes one click, and turns your humble kit lens into L class glass*
http://www.dpreview.com/lensreviews/canon_18-55_3p5-5p6_is_c16/page4.asp
Here is more evidence, with DPP applied to the 17-85mm,
http://www.dpreview.com/lensreviews/canon_17-85_4-5p6_is_usm_c16/page3.asp
and 18-200mm
http://www.dpreview.com/lensreviews/canon_18-200_3p5-5p6_is_c16/page3.asp
And for comparison, a review of the Sigma 18-200mm OS:
http://www.dpreview.com/lensreviews/sigma_18-200_3p5-6p3_os_n15/
* Well, a heck of a lot better than you might expect for the price
