Incremental zoom bookmarklets: !ZoomInIn and !ZoomOutOut (drag to Links-bar). Works best in IE5 (IE6 won't resize positioned elements). Source:

javascript:if(!document.z){void(document.z=1);}void(document.z*=2);void(document.body.style.zoom=document.z);void(document.body.parentNode.style.zoom=document.z);

javascript:if(!document.z){void(document.z=1);}void(document.z*=0.5);void(document.body.style.zoom=document.z);void(document.body.parentNode.style.zoom=document.z);

Update: I forgot, pup already made these.