Well, that's a tricky one.
Signed soccer jerseys are sold all over the world. The main markets are probably latin-american ones, and there's an alert trade in football memorabilia in a site called www.mercadolibre.com.
Of course you can try and post it on ebay, however, you'll find that most of the sport-memorabilia sold over there is more baseball-NFL-hockey-rugby related (you might wanna try a local ebay site, for the european countries, where football is more popular).
When you publish the item for sale, try to emphasize the stars of the 2002 squad, such as Raul, Hierro, Morientes, Casillas, Puyol and Mendieta. That might raise the sum a bit.
The problem is that Spain is not quite the most popular national team in the world. Most people prefer their own country's team, and then pick another one, generaly Brazil, as the team to support, in case their own doesn't make it to the world cup finals. Spain isn't the natural choice for most people, since they're somewhat losers when it comes to the major events. That might make your job a bit harder.
Try to check some spanish sites and see if you get any luck there (although my guess is that spain is the place with the major supply of such shirts, so I guess demand won't be very high).
You can also try the users forums for spanish league teams fan clubs. There are such fan clubs all over the world (especially for Real Madrid, Barcelona, Valencia etc.). You'll probably find an Israeli fan club for these teams. I guess a Real Madrid fan would buy such a shirt since it has some popular Real players signatures on it.
Another option is to try and sell it to some sports-bar, that hangs this kind of jerseys on its walls.
Another thing to consider is that 2002 wasn't such a long time ago. These shirts aren't really rare yet, and I believe these players signed lots of jerseys for commercial uses. You might wanna consider keeping it for another 10 years or so, and then try to sell it as a rare item, to someone who grew up watching that team, having nostalgic memories of it.
The more you wait, the more you can charge for the shirt. collectors that pay lots of money on these things look for old and rare stuff. not new.
In order to evaluate the price range you should look into several things:
- was the shirt ever used?
- is it an original authentic Adidas Jersey or some replica?
- Have all the players signed? can you identify each player's signature?
now search for similar products in the web site you plan to post yours. see other national teams (I just saw the 2002 Brazil signed jersey for 500 Australian $ on ebay australia, but bear in mind that brazil were world champions in that tournament so their shirt would end up being much more expensive than yours).
Of course you might wanna take into account the price you paid for the shirt itslef as a bottom price, so that you don't lose money on this deal.
Personally I don't think I would give away such a shirt. Some really good players signed it, and it is a great souvenir to show your grandkids someday...