How to handle timed out connections

[Lars Hoeyrup Jensen]

I have a program that tries to connect to a certain web page with
urlopen(). Sometimes the page doesn't respond: if I try to open it in
Netscape, after a couple of minutes I get a message like this:

"ERROR

The requested URL could not be retrieved

.....

(110) Connection timed out

...

Generated by .... (Squid/2.2.STABLE4)"


How do I handle this in Python? I would like to generate a message
like "The page is currently down" or something if the page doesn't
respond, but I don't know how to "detect" this timeout in Python.

Thanks in advance,
Lars