It is a bit tricky to figure out your scenario, but if you have your text and your check box in an surrounding element like the following:
<form>
<!-- Other form elements -->
<span><input type="checkbox" name="user_terms" value="accepted">I accept these terms!</span>
<!-- Other form elements -->
</form>
Then you can select the check box with the following Selenium IDE command:
<tr>
<td>click</td>
<td>xpath=(//input[contains(ancestor::span/text(),'I accept')])</td>
<td></td>
</tr>
This translates to the following Xebium line
| ensure | do | click | on | xpath=(//input[contains(ancestor::span/text(),'I accept')]) |
Note, in this case I used a <span>
tag, but this can of course be altered as well.