benh,sur ton bouton par exemple ,tu mets ca :
<form name="form1" method="post" action="">
<input name="Submit" type="submit"
onClick="MM_openBrWindow(´http://www.skateboarding
.c.la´,´´,´´);MM_openBrWindow(´URLTELECHAGEMENT´,´
´,´´)" value="Telecharger !" >
</form>