The North American affiliate site is LightningMaps.org.
In addition to tracking lightning stikes, you can overlay satellite and radar data; and even set the maps to show you approximate thunder propagation.
Select the realtime option (e.g. http://www.lightningmaps.org/realtime) and zoom way in on any storm. Select the thunder option under the settings (gear) menu, and you'll see the strikes as yellow dots, with thunder shown in animated circles, expanding from each mapped strike.
Here's a still image, grabbed from current storms in northern Vermont, with the thunder, clouds, and radar options all on.
There are many weather apps, but this is the only one I've seen with thunder. :)