Increase Selenium timeout value

I am testing a slow loading page with Selenium (html recorded by Selenium IDE) but it always fails due to timeout. The default timeout value is 300000, i.e., 30 seconds. I know, I know - it is plenty of time and something needs to be done to that page. The question here, however, is how to increase Selenium's timeout to get the test passed.

I can specify the timeout value at the beginning of the html script like

<tr>
<td>setTimeout</td>
<td>600000</td>
<td></td>
</tr>

Now the test passed happily.