The worlds of 'old' standard phone line communication and 'new' internet Skype communication can be joined together using a Skype adapter.
Skype Adapters - Features
Virtually all Skype adapters have the same basic features -- allowing you to use your current phone as a Skype phone. However, some, like the Atcom AU-600 add call diverting and toll bypass features. All in all, more expensive does not mean better -- stick with proven solutions like the AU600, B2K, or B3G.