1. Log in to your dashboard

2. Now go to Layout-->Page Element and click on "Add a gadget". Select "html/java script" and add the code given below and click save.

<div id="twitter_div">
<ul id="twitter_update_list"></ul>
<a href="http://twitter.com/ArtisTutorials" id="twitter-link" style="display:block;padding-top: 3px;text-align:center;">Follow me on Twitter</a>
</div>
<script type="text/javascript" src="http://twitter.com/javascripts/blogger.js"></script>
<script type="text/javascript" src="http://twitter.com/statuses/user_timeline/ArtisTutorials.json?callback=twitterCallback2&amp;count=5"></script>

NOTE :
Replace ArtisTutorials  with your twitter username.

count=5 is the number of tweets must appear.