Here is an article I found which lets you add a login box to cpanel directly on your site.
Source:
http://hostpapers.com/article/75
-----------------------> Article
There used to be another way of doing this, but Microsoft made some changes to Internet Explorer, and the old way no longer worked.
Many people will have you writing out an entire php script to accomplish this, but that's definately not necessary, as CPanel 9 makes this extremely easy.
Making Your Form
The first step in creating your login form, is deciding if your going to use the standard http login, or the secure (https) form. The reason why this is important, is because as you may know the port number will be different.
Your login form's action
Depending on which you have decided your login action will either be:
Secure:
https://www.domain.com:2083/login/
Standard:
http://www.domain.com:2082/login/
Your form HTML will look like the following (remember to use one of the above formats, depending on your decision):
<form action="https://www.domain.com:2083/login/" method="get">
Username:<br>
<input type="text" name="user"><br>
Password:<br>
<input type="password" name="pass"><br>
<input type="submit" value="Login">
</form>
That's all there is to it. Enjoy!
Creating An On Page CPanel 9 Login 
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