Put your email in a widget

You might want a link in your sidebar so when people click it their email program opens and they can send you an email.
You can do this with a text widget.

Note: Doing this exposes your email address to spammers.
You WILL get more spam by doing it this way.

In a text widget, write this (use your email address of course!):
<a href="mailto:trash@wordpress.com">Email me!</a>

You might want to filter the email from your blog.
In this case you can make the email program complete the subject for you:
<a href="mailto:trash@wordpress.com?This is from your blog">Email me!</a>

A much better way is simply to list your email:
trash at wordpress dot com
or
trash @ wordpress . com
as the spammers will not get the address then.