Streaming requires utilizing a multicasting server or a multicasting service. Most people opt to use the service because of the expense and knowledge of the technology involved in setting up your own server. Setting up your own server requires a fairly beefy machine, however most of the expense can be found in the bandwidth necessary to provide feeds for everyone who wants to see your live content. For every outbound feed to a viewer you need upload bandwidth comparable to your stream settings. For example, if you stream your content at 512 Kbps and 100 people simultaneously view your feed, then your upload bandwidth requirement is 512,000 Kbps.
512 Kbps X 100 = 51.2 Mbps (upload bandwidth needed)
Finding an Internet Service Provider to offer you a 52 Mbps upload speed is almost impossible unless you are using asynchronus data connection in fiber optics which can be extremely expensive. Therefore, the best bet is to use an outside multicasting service that has the needed bandwidth to provide streams to your viewers.
Once you have decided on a multicasting service and you have your video and audio feeds coming into your computer then you need to send your programming out. To do this you need a piece of software that connects your feed to the multicaster. There are plenty to choose from, but if you are on a budget I would recommend Adobe Flash Media Live Encoder.
Adobe Information can be found HERE.
This software is very configurable taking your media stream and connecting it to a multicasting server. It gives you flexibility to configure the parameters of your stream quality and bandwidth. It also has the ability to save your stream to a file for editing or uploading to your favorite video archive and playback service like Vimeo.
The Flash Media Encoder is a fairly simple software to configure and use. Spend some time testing your settings to assure you have the best streams for your viewers. Too much bandwidth restricts your viewers to broadband and too small bandwidth reduces video quality. There are compromises so you have to test to see what works best for you.
The best thing about Adobe Flash Media Live Encoder is that the software is a free download from Adobe. Have fun streaming!