We introduced quite some proxies for Sprie, the legal Siri portable from Cydia, however they are always unstable - that's really embarrassed... Today I just find another Spire proxy called WordJelly, which introduced by folks from JailbreakHow. This video shows the steps from how to install Spire to proxy connection. According the publisher of the video, the proxy works best among all the proxies. If you still have your devices below firmware 5.1, it should works, since Spire doesn't support firmwares higher than iOS 5.1.

via wikijailbreak