Any sugestions ?

How to creat something like guestbook
Just it should be something like if email is wrong it wount e added to list.

Gathering real-life e-mail addresses inside SL would very probably be a TOS infringement.

You can however gather SL names perfectly well. I'm not at my SL machine at the moment so I can't test compile this but it should be close:

list guests = [];

default {
    state_entry() {
        llSetText("Touch me to sign guestbook.",<1.0,1.0,1.0>,1.0);
    }

    touch_start(integer detected) {
        // Owner wouldn't generally want to sign their own guestbook
        // So if they click, assume they want to view it
        if (llDetectedKey(0) == llGetOwner()) {
            // Print out all guests
            integer t;
            for (t=0; t<llGetListLength(guests); t++)
                llOwnerSay(llList2String(guests,t));
            // Reset guest list            
            guests = [];
        } else {
            string their_name = llDetectedName(0);
            // See if their name is already in list
            // Prevents griefing by multiple clicking until storage runs out
            if (llListFindList(guests,[their_name] == -1)) {
                // Not already in list, add it
                guests += their_name;
                llSay(0,"Thank you, " + their_name + "!");
            } else {
                // Already in list, say so
                llSay(0,"You have already signed the guestbook, " + their_name + ".");
            }
       }
    }
}

Of course, if you are having so many visitors that the script memory limit runs out between visits to clear the guestbook, then extra things might be needed. But if that's the case, you can afford to bally well pay for a script

Yeah, thanks ;D For not working script Could u fix it ? i need it wery much