See svgweb quickstart and the svgweb project homepage for something that works in all browsers including IE (requires flash plugin).
There are many ways to include an existing svg file:
<img src="https://stackoverflow.com/questions/2011289/your.svg"/><object data="https://stackoverflow.com/questions/2011289/your.svg"/><iframe src="https://stackoverflow.com/questions/2011289/your.svg"/><embed src="https://stackoverflow.com/questions/2011289/your.svg"/><div style="background:url(your.svg)">...</div>