How to manually cache a block?

Hi,

I have a few blocks whose data I would like to cache for at least a month. I don't understand which code should I put in the block to do this. Can someone please provide me an example?

There should be the following properties:

Cache-Control: max-age;
Expires
Last-Modified

This is the example of one of the blocks I'd like to cache (Google CSE):

<STYLE>
#cse-search-box input[type=text] {
float:left;
}
#cse-search-box input[type=submit] {
float:left;
margin: -21px 0 0 3px;
}
</style><form action="http://www.123.com/123" id="cse-search-box">

<div>
    <input type="hidden" name="as" value="partner-pub-xyxyxyxyxyxy:xyxyxyxy" /><br />
    <input type="hidden" name="asd" value="FORID:10" /><br />
    <input type="hidden" name="ias" value="UTF-8" /><br />
    <input type="text" name="as_q" size="25" /><br />
    <input type="submit" name="as" value="123" />
  </div>
</form>
<script type="text/javascript" src="http://www.google.com"></script>

I'm using an Apache server.

Thank you in advance.