I  have  some  confusion about my pic for  green  card lottery.My pic is in jpg format but jpeg format is  required for dv  . is jpg and jpeg   same ? How can i change it to jpeg format.

Another  question is how  to know  that my pic has 24 bit colour depth.  How  can  i   change the image colour depth of digital pic?

Any help would be appreciated.

RC,
Here is the info you requested:
The most common filename extensions for files employing JPEG compression are .jpg and .jpeg, though
.jpe, .jfif and .jif are also used. The file extension does not matter as long as it is in Joint Photographic Experts Group standard. That's what they are looking for.
Regarding your 2nd question, as long as you did not borrow the camera from some museum to take your picture, you should be fine. j/k.
When you save your image as jpg, jpeg etc, the standard format is that it
is saved in 24-bit color.
(They know not everyone works for Adobe and what they are asking for is pretty simple.)

which site is for filling dv form can u help me out

here is where you should follow how to file for DV 2011.
http://www.dvlottery.state.gov/

can we use last years photo?? i know it says 6 months but would they find out? any similar situations who won the lotteries.. THANKS

don't use last year's photo. follow this:

se IdPhotos 2008 3.6.3, u can download this at : http://download.cnet.com/IdPhotos-2008/3000-2192_4-10857162.html. just having the right image size does not meet the requirements. and the photo validator just makes sure it's with the right size. you need to make sure you meet other requirments too. Read the instructions at the dv website and use this tool. use can select dv2011 format for the dv 2011.  good luck.