tried to update my iphone 3, but after going to settings/ general there is no software update tab.

I have the Weather network app. I did a update on this app. then the app stop working. I removed and installed a couple times. I have just tried to update from apple Iphone link. going to settings / general/ software updates. there was no tab (software updates) I also rebooted the phone- holding sleep and home tell the apple logo apeared.

Now what???