HTML-layout problem with XSLT

Hi!

I´m trying to make create a html-table using XSLT. The result i want is something like this

<tr class="styleOdd"><td>Some text</td></tr>
<tr class="styleEven"><td>Some other text</td></tr>

The problem is that I have no idea how to get it to switch the class (styleOdd/StyleEven) for every row in the table. How is it possible to "know" which one that is to be outputted?

In "PHP-language" for i.e the same thing would look something like this

<?php for ($i = 0; $i < $y; $i++) {
if ($i % 2 == 0) {
echo "<tr class=\"styleEven\"><td>Some text</td></tr>";
} else {
echo "<tr class=\"styleOdd\"><td>Some text</td></tr>";
}
} ?>

Need I say that I´m new to XSLT