i have a project which does this. It goes like this:
Pulsar Analog Source (which has my mic attached) into a MicroMixer (1) Input 1. Then MicroMixer (1) out Mix LR to 24 Bit Wav Dest (ie. Skype - they can now hear you) and also feeding MicroMixer (2) Input 1. Then i have 24 Bit Wav Source feeding Input 2 of MicroMixer (2). Feed output of MicroMixer (2) to Pulsar Analog Dest (which feeds your headphones), then you can hear yourself and the caller, but the caller only hears you. i only really have the first MicroMixer to control the mic level, but you could put the a Pulsar mix through it to do your streaming.
i use an SM58 mic and Beyerdynamic DT150 - bit of overkill for Skype

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