This is usually surprisongly easy to repair using the techniques described on the 'net for fixing a Playstation2 with the same problem.
If you're not too scared about opening up your DVD player, try this page:
If target=_blank>http://www.techtv.com/xplay/features/story/0,24330
,3516150,00.html
If
you're going to replace it otherwise, it's worth a try anyway. In place if the alcohol, you can use any non-smear glass cleaner (I use Windolene spray).
You may not necessarily be able to raise/lower the laser housing in a DVD player in the same way as a PS2, but in my experience, it's not necessary, as sometimes just cleaning the lens properly does the trick.
I've now 'repaired' three different players, as well as my PS2 like this, and they all work excellently now.