Here are the codes I use to create a custom Twitter feed for my websites which includes retweets.
First you will want to insert the Javascript that makes the whole thing work. Copy and paste this line of code into your website, preferably just before the closing <body> tag:
<script src="http://twitter.com/javascripts/blogger.js" type="text/javascript"></script> <script src="http://api.twitter.com/1/statuses/user_timeline.json?screen_name=thelibzter&include_rts=1&callback=twitterCallback2&count=6" type="text/javascript"></script>
Replace the words THELIBZTER in the above example with your own Twitter username. Change the number 4 after “count” to the number of tweets that you want to display.
Next, copy and paste the following html into the web page where you want the Twitter widget to display:
<div id="twitter"> <div id="twitter_t"></div> <div id="twitter_m"> <div id="twitter_container"> <ul id="twitter_update_list"></ul> </div> </div> <div id="twitter_b"></div> </div>
And, finally, copy and paste the following CSS into your website’s stylesheet:
#twitter {
-webkit-border-radius: 5px;
-moz-border-radius: 5px;
border-radius: 5px;
width:430px;
border:1px solid #c9c9c9;
}
#twitter_t {
width:405px;
height: 44px;
background:#c68aeb url(yourimagehere);
color:#fff;
text-shadow:.5px .5px #333;
font-size:18px;
font-family:Candara;
padding-top:20px;
padding-left:25px;
}
#twitter_m {
width: 400px;
padding: 0 15px;
background:#f7effc;
}
#twitter_container {
min-height:45px;
height:auto !important;
height:40px;
padding-bottom:5px;
padding-top:5px;
}
#twitter_update_list {
width: 413px;
padding: 0;
overflow: hidden;
font-family: Georgia;
font-size: 14px;
font-style: italic;
color: #31353d;
line-height: 16px;
font-weight:bold;
margin-left:-13px;
}
#twitter_update_list li {
width: 400px;
list-style: none;
padding:15px;
border-bottom: dotted 1px #ccc;
}
#twitter_update_list li a {
color:#631891;
text-decoration: none;
}
#twitter_update_list li a:hover {
color: #31353d;
}
#twitter_b {
width: 430px;
height: 29px;
background:#c68aeb url(yourimagehere);
}
Of course, you will probably want to edit the CSS codes for your Twitter widget.
And that, my friends, is all it takes to create a custom Twitter widget for your website! 
Have fun, and let me know if you run into any issues.
FURTHER READING:
If you want to remove the time stamp from the tweets in your custom Twitter feed, please check out this post – http://icode4you.net/creating-a-custom-twitter-feed-how-to-remove-the-time-stamp-from-tweets.
Make sure you also check out another post I wrote that has the styles for several different custom Twitter widgets that are all ready to incorporate into your website!
And here is a link to a post that provides the codes and instructions on how to create a Twitter feed of the search results for a certain term.