Spire is available via Cydia itself and takes little space. During the installation will be contacted Apple's servers where to direct the Siri necessary files to download, with approximately 100MB of data will be stoked. Users are therefore advised to Wi-Fi on, before starting the installation of Spire. To Siri through Apple's servers to use, you will still need to have an authorization token from an iPhone 4S or need to connect through a proxy Siri. For this reason, Spire will be able to address itself to fill a proxy server.
To make use of Siri through a proxy on an older iPhone, iPod touch or iPhone you can use westbaer's SiriProxy fork. You can use this proxy instance if you own an iPhone 4S, or you know someone who is your authorization token to share. Other options are to use a proxy Siri third, where you have to look to your contacts, email, SMS and GPS information through a malicious proxy server may leak. Another possibility is that someone finally enables Siri soon be used in combination with eg Google Chrome's speech API. Spire is (still) not suitable for use with SemiTether .
Spire is freely available via the BigBoss repository