(2-part post):
If you normally access your email via a web page (rather than by using an email client, such as Outlook Express or Windows Mail) you can do so in exactly the same way as you would from home.
If you normally access your email via an email client (Outlook, Outlook Express, Windows Mail, Thunderbird, etc), the easiest way to access your mail from another location would be to switch to web-based access. Most (possibly all?) ISPs allow you to do so. Simply go to the home page of your ISP (or of the company which provides your email service, if different) and look for a link such as 'email', 'my mail', 'user login', etc. You'll be asked for your username and your password and then you'll be taken to a page where you can click on things like 'Inbox', 'Compose mail', etc.
You don't need to wait until you're using another computer. You can try using the web-based service right now, from your home PC.