An alternative way i've used to test Twilio till now is get a DynDNS account and point it to my home laptop. Infact my home router has a DynDNS option to fill in my username/password, so it can query the latest external domain assigned to it. This is useful if you're on a DHCP and don't have a static IP.

You get a domain like blah.ath.cx that you can use.