Thanks for all your help... I looked into the options you suggested, but, not being much of a guru of css, I couldn't really work much out... was a bit concerned, as my funky button is only funky as it has an 'onMouseOver' setting...
Anyway, I have found that I can actually set the submit button to just be a gif that I have simply in html. For those of you that are interested, here's what it is.... (forgive me for putting html solutions in a php forum!!)
<form action="nextpage.php" method="post">
<input name="custid" type="text" value="username">
<br>
<input name="custpwd" type="password" value="password">
<input type="image" src="images/go.gif" onMouseOver="MM_swapImage('Image3231','','images/go_f2.gif',1)" onMouseOut="MM_swapImgRestore()" alt="go" name="Image3231" width="14" height="10" border="0" align="right" id="Image3">
</form>
Hope this might help some people.