If you want to get a practical exposure there are few options.
*Set up your own lab -
If you are planning to go for CCIE voice this would be a good choice but bit costly. Unity server, and the Cisco Unity Express. I used 3640 routers instead of the 3725 routers....GWGK multiple Call Manager servers, For QOS couple of routers and a couple of voice routers (FXS and FXO cards, NM- V1 or NM-V2 to hold them, depending on your routers) to generate some RTP traffic like wise.
Rack rentals If you don't have access to Voice Lab equipment at work, most people will rent rack time and maybe get some of the (cheaper) equipment off of eBay.
*****Participate in a CCVP course
There are training institutes who provides hands on labs for CCVP. If you are in UK close to London WinNET Systems is a good choice who provides physical lab access and practice labs.
Hope this will help you!!!