update
I decided to take the plunge and got the iRig adapter thing from my LGS today
I’ve downloaded the free amplitube app – and it seems really good
You get a “marshall stack” type amp and a delay in the free app, plus a distortion pedal when you register.
I’ve shelled out for a couple of my favourites (fender 65 deluxe amp and a tube screamer type pedal) – and I’m very happy – the sounds are very good, better than my POD (hardly surprising as that is getting on for 10 years old now)
Only thing to be aware of – the iRig + guitar cable = heavier than an iphone. I imagine it would be quite easy for your phone to be dragged to the floor by accident, so be careful out there