funziona

ora però ho messo

#menu ul li #home a :hover per fargli comparire un immagine sopra quando passo col mouse

sai cosa fa ???
fa un hover con le regole di tutti gli altri link , cioè fa un hover con background nero , io invece voglio solo che cambi l immagine di sfondo.
è la prima volta che affronto una cosa simile


.jqueryslidemenu{
font: "Trebuchet MS", "Tw Cen MT";
width: 1088px;
background-image: url(../images/mainmenu.gif);
height: 42px;
margin-right: auto;
margin-left: auto;
background-repeat: no-repeat;
}


.jqueryslidemenu ul{
margin: 0;
padding: 0;
list-style-type: none;
}

/*Top level list items*/
.jqueryslidemenu ul li{
position: relative;
display: inline;
float: left;
}

/*Top level menu link items style*/
.jqueryslidemenu ul li a{
display: block; /*background of tabs (default state)*/
color: #000000;
text-decoration: none;
height: 26px;
width: 155px;
text-align: center;
margin-top: 5px;
padding-top: 8px;
border-right-width: 1px;
border-right-style: solid;
border-right-color: #000000;
font-family: "Trebuchet MS", "Tw Cen MT";
font-size: 18px;
padding-bottom: 2px;
}

* html .jqueryslidemenu ul li a{ /*IE6 hack to get sub menu links to behave correctly*/
display: inline-block;
}

.jqueryslidemenu ul li a:link, .jqueryslidemenu ul li a:visited{

}

.jqueryslidemenu ul li a:hover{
background: black; /*tab link background during hover state*/
color: white;
}

/*1st sub level menu*/
.jqueryslidemenu ul li ul{
position: absolute;
left: 0;
display: block;
visibility: hidden;
}

/*Sub level menu list items (undo style from Top level List Items)*/
.jqueryslidemenu ul li ul li{
display: list-item;
float: none;
}

/*All subsequent sub menu levels vertical offset after 1st level sub menu */
.jqueryslidemenu ul li ul li ul{
top: 0;
}

/* Sub level menu links style */
.jqueryslidemenu ul li ul li a{
width: 155px;
margin: 0;
border-top-width: 0.5px;
border-top-style: solid;
border-top-color: #000000;
height: 25px;
padding-top: 5px;
font-family: "Trebuchet MS", "Tw Cen MT";
font-size: 12px;
}

.jqueryslidemenuz ul li ul li a:hover{ /*sub menus hover style*/
background: #eff9ff;
color: black;
}

/* ######### CSS classes applied to down and right arrow images ######### */

.downarrowclass{
position: absolute;
top: 12px;
right: 7px;
}

.rightarrowclass{
position: absolute;
top: 6px;
right: 5px;
}
#myslidemenu ul.currentli {
background-image: url(../images/backul_li.jpg);
background-repeat: repeat-x;
}


.jqueryslidemenu ul li#home {
display: block; /*background of tabs (default state)*/
color: #000000;
text-decoration: none;
text-align: center;
border-right-width: 1px;
border-right-style: solid;
border-right-color: #000000;
font-family: "Trebuchet MS", "Tw Cen MT";
font-size: 18px;
height: 40px;
width: 155px;
}

.jqueryslidemenu ul li#home a {
display: block; /*background of tabs (default state)*/
color: #000000;
text-decoration: none;
text-align: center;
border-right-width: 1px;
border-right-style: solid;
border-right-color: #000000;
font-family: "Trebuchet MS", "Tw Cen MT";
font-size: 18px;
background-image: url(../images/homgifbs.jpg);
background-repeat: no-repeat;
background-position: center center;
text-indent: -99999em;
height: 26px;
}
.jqueryslidemenu ul li#home a:hover {
display: block;
text-decoration: none;
text-align: center;
background-image: url(../images/homgif.jpg);
background-repeat: no-repeat;
background-position: center center;
text-indent: -99999;
}