I can't find otool on my jailbroken iPod
When you change your settings to Developer in Cydia, what you are actually doing is changing the package list filter. This means that certain packages will only be shown as available to download and install in the package list according to which filter you select.

Having set your filter settings to 'Developer' you'll then need to find and install the package you want.

otool is included in the package called: BigBoss Recommended Tools