penders - 11:25 pm on Nov 30, 2011 (gmt 0)
lucy24's solution is a good alternative and can be achieved with the same/similar markup. Float the <span>.
Both have good browser support AFAIK. Although IE6 might be a problem.
ps would be able to force the span in the above (my example) to take up the remaining text of the paragraph without writing extra characters?