@harrydoy As well as setting up a security PIN, you may want to set voicemail to send you a text alert when you have voicemail, rather than have the service call you back. Otherwise, if voicemail alerts you by calling your phone, you will be charged for the incoming call, or it will be deducted from your current allowance of calls. You'll find instructions for both on http://support.vodafone.co.uk/Using-our-network/Voicemail/
As AnnS says, you can access voicemail by calling 07836 121 121 from any phone, and entering the required details. So you just have to work out what is your cheapest option. Depending a bit on the contracts you have, calling from a landline, from a different mobile, or using skype may be cheaper than using your Vodafone PAYG. I have a certain number of skype minutes per month with my subscription to MS Office, so I use that if my call allowance with Vodafone is getting low.
