A couple of useful links:
"Say No to 0870" Phone numbers - also 0871 0844 and 0845
Enter either the name of the company or the expensive 0870, 0871, 0844 or 0845 number to find the equivalent Freefone or geographical (01, 02 or 03) phone number and save yourself pounds!
Say No To 0870
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Find out all about the new IPv6 IP addresses ...
... which start rolling out soon eventually to replace the current xxx-xxx-xxx-xxx version 4 addresses.
IPv6 Test
Also see this Wikipedia explanation:
Wikipedia - IPv6