For the most accurate results, use the new TwitchTest tool instead of this, as TwitchTest will also do a test stream and monitor your bitrate and connection stability.
Update (Jan 2014): Now uses the new Twitch API rather than the old undocumented XML ingest list (the latter no longer appears to be maintained).
Download (requires .NET 3.5, if you can run XSplit you already have this):
+ Show Spoiler [How to set your ingest server in OBS] +
Settings / Broadcast Settings / Server.
+ Show Spoiler [How to set your ingest server in XSplit] +
Broadcast / Edit Channels / Edit / Location.