In various discussions I've mentioned software I find useful with PlayIt Live. This is my list of some "useful tools".
Firstly a streaming player application with metering.
There are probably others but I like Screamer
The previous version (0.44) is more useful in some respects as (with some fiddling) it will record streams.
MP3 Gain Normalization
Without getting into the reasons why, MP3s (however sourced) tend to have differences in both absolute and perceived level.
There are other solutions but I like MP3 Gain.
This can (roughly) fix apparent loudness differences between files. Use it on a copy of files just in case.
MP3 Tag Editing
My current favorite for this is
MP3 "Top and Tailing"
While obviously if you have the original uncompressed audio, editing using Audacity (or similar) is best, if all you have is the MP3 and you need to trim silence or "tighten up" live recording files then an editor that works on MP3 files is good.
It can also join MP3 files together (although you need material at the same constant bit rate for that to work well).
The PlayIt Live Streaming plugin is good abut it is useful to have metering of the streamed level available, particularly if you run PlayIt Live on one screen full size but have a second screen available (for example if you have a laptop and a separate monitor as an extended desktop).
Broadcast Using This Tool (B.U.T.T.) is worth trying.
For a very well featured (particularly in the paid version) streaming application, Rocket Broadcaster is also worth a look.
I particularly like the way it tests the streaming settings and suggests what you might have got wrong !
Also, you can mix "internal" audio from a PC and an input (say from a mixer) so you could effectively "bypass" your mixer while in full automation by muting the "Microphone" and enabling "other applications" and then "go live" by muting "other applications" and enabling "Microphone"