[garry22]

Do you ever get loads of calls from a number you don't recognise?

Try this    http://whocallsme.com/

It's a sort of forum where people share numbers of phone nuisances. I've got a shortcut on the desktop so I can look them up before answering (or not).

[Matt Seymour]

Yep, I often use that service myself.

Comes in very handy.

[Adam P]

or just google the number...