<div id='gb_einträge '>
<div class='gb_beitrag_rechts'>Hier steht der GB eintrag!</div>
<div class='gb_beitrag_links'>'xHTML' schrieb am<br/>    Samstag, 7. März 2009<br /></div>
</div>

#gb_einträge {
    position: absolute;
    width: 100%;
    top: 0px;
    bottom: 130px;
    overflow: auto;
}

.gb_beitrag_links {
    position: absolute;
    height: 100px;
    width: 280px;
    border: 1px dotted #90909B;
    font-size: 16px;
    padding: 5px;
}

.gb_beitrag_rechts {
    position: relative;
    height: 100px;
    left: 290px;
    width: 508px;
    margin: 10px;
    padding: 5px;
    border: 1px dotted #90909B;
    overflow: auto;
    font-size: 16px;
}

<form name="formaction" action="?seite=gaestebuch" method="post">
    <div id="gb_formular"><hr>
        <div id="gb_formular_text">
        <label>Text: <br /><textarea name="Inhalt" rows="3" cols="35"></textarea></label>
        </div><div id="gb_formular_spam">
        Sicherheitsabfrage, gegen Spambots:<br />
        <label>3 + 5 = <input type="text" name="Antwort" maxlength="2" size=1 /></label>
            <input type="hidden" name="Rand" value="8"/><br /><br />
            <input type="submit" name="formaction" value="GB Eintrag abschicken" />
        </div>
        Ins Gästebuch Eintragen:<br />
        <label><div class="gb_formular_name">Name: </div><input type="text" name="Autor" /></label><br />
        <label><div class="gb_formular_name">E-mail: (opt.)</div><input type="text" name="Email" /></label><br />
        <label><div class="gb_formular_name">Homepage: (opti.)</div><input type="text" name="Homepage" /></label>
    </div>
</form>

#gb_formular {
    position: absolute;
    left: 0px;
    right: 0px;
    bottom: 0px;
    height: 125px;
    font-size: 16px;
}

.gb_formular_name {
    position: relative;
    float: left;
    width: 120px;
}

#gb_formular_text {
    position: absolute;
    left: 300px;
    width: 400px;
}

#gb_formular_spam {
    position: absolute;
    left: 640px;
    width: 120px;
}