How do I upload a file or demonstrate a composition without having a website?
send me a PM, (click on my name) and I will send you my email address, then you can email me the MP3. I will be happy to upload it to my webspace for a few months, I will also provide you with the "link" and directions on how to post it.
There are always very kind people around here like DPDan who are happy to host music on their space for other GPO users.
If that makes you feel 'obliged' then try one of the free hosting/storing facilities like eSnips (but I do see a negative post on this particular one a few lines up hmmm).