First, according to Microsoft's "My Hotmail account was upgraded to Outlook.com" FAQ, you "can keep using your existing @hotmail.com, @live.com, or @msn.com address." So you don't even have to change your email address; the only thing changing is the email service.

To answer your question, yes, people will receive emails sent to their old hotmail.com addresses...

"The Hotmail address will become an alias to the outlook.com account.  The login will be to the outlook.com account."