This integration is intalled by default when you install ACT!. You can find it in Internet Explorer under the Tools Command Bar. This is not the menu bar (i.e. File/Edit/View…), rather is usually found towards the right-hand side of the screen, just above the actual web page. If you have tab viewing implemented, it might also be on that same level.
Click on that menu item, choose Attach Web Page to ACT! Contact, which will bring up, from ACT!, the Select Contact window. Choose a contact, and click OK.
Hope this helps, thanks…