I guess you use float to position them next to each other.
You can wrap around the two divs with another div of a minimum width you want the page to be viewed in.
that will stop the second one from dropping below the first one
<div id="wrapper">
<div id="logo">...</div>
<div id="text">...</div>
</div>
style for it would be:
#wrapper { width: 980px; }
#wrapper div { float: left; }
#logo { width: 200px; }
#text { width: 780px; }
something like that.
if someone resizes the window to be narrower than 980px (or uses lower screen res) then you'll get horizontal scroll.
//edit
in response to comment you can use min-width to make it more flexible. will cause IE
#wrapper { min-width: 980px; }
#wrapper div { float: left; }
#logo { width: 200px; }
#text { min-width: 780px; }
min-width isn't supported by IE6 so you may need fix for that.