I would like to have my own logon/login page instead of using your page. Can I customize or create my own page for loggin in?

Yes! Here are the details:

Create your own page and make sure it POSTs these form variables to this url:
http://login.salesjunction.com/login.asp?coid=yourcoid

userid:theuserid
pwd:thepassword
OL0:yourcoid
LOGON:GO
Login:login
Submit:Login

So your HTML page would look like this: