In general, yum repositories are accessed over http or ftp. You can use any number of freely available http or ftp servers. Typing "creating a yum repository" (without quotes) into Google yielded this page:
http://www.techrepublic.com/blog/ope...repository/609
I suggest that you look through it and some of the other results and then come back here to ask any
specific qestions that you might have.