Patty--More information and history can be found here.
http://www.gunsworld.com/walther/p38_home_us.html

Auctionarms.com shows wide variation in current values, likely based on condition and rarity (original manufacturer) & age -- sorta like how we value chips :-)
http://www.auctionarms.com/search/auctions(1).aspx?&aa=p38&aj=1

Please be careful. My uncle kept a similar souvenir from the war--and late in the 70's after his death, it was finally unloaded for the first time. Have someone who knows what they are doing check it to make sure it's safe before handling. Be careful of your state laws on possesion of firearms and handguns specifically.