Opening pdf files on 9.04

[Graham Watkins]

Hello folks,

I've just installed Ubuntu 9.04 after sticking with 8.04 for about 18 
months.  On the whole I'm pleased with it but I do have one niggling 
problem that I hope can be easily resolved:

Whenever I double click on a pdf file it is opened with Gimp rather than 
the Document Viewer or XPDF.  A small thing perhaps but mighty 
irritating.  I can open them if I remember to right click then select 
one of the latter.  But what I really want is a way of altering the 
association with PDFs so that they are opened by a pdf viewer by default.

Is there an easy way of implementing this?

Cheers,

Graham