To embed this button to your own website, just copy-paste the following block of HTML code anywhere in your website. Then replace XYX in the subscription URL with your own YouTube username.
<iframe src="http://www.youtube.com/subscribe_widget?p=XYZ" 
       style="overflow: hidden; height: 105px; width: 300px; border: 0;" 
       scrolling="no" frameBorder="0">
    </iframe>

One-Click YouTube Subscribe Button

When you create a link from the website to your YouTube channel, there’s a probability that that visitor may fail to notice the “subscribe” button on the already crowded YouTube channel page.

However, if you add “sub_confirmation=1″ to the YouTube channel link, the visitor will get a prompt to subscribe to your channel while they are on the YouTube website. Click here for a live example.

http://www.youtube.com/user/MyInstantSearch?sub_confirmation=1
Please do note that the Subscribe prompt would not be displayed if the visitor is already subscribed to your YouTube channel or if they are not logged into YouTube.