Ich habe ein Eis gegessen - I have eaten an ice cream
Ich bin in die Schule gegangen - I've gone to school
You can listen to this podcast directly on your computer by clicking here.
While I was researching this podcast, I found a couple of particularly useful websites. Here are the English ones:
A description of when to use the different German past tenses:
A description of how to use the German perfect tense:
Exercises (particularly suitable for beginners) to practise using the perfect tense:
And here are the German ones (two descriptions of when Germans say you should use the perfect tense and when the simple past (also known as the imperfect tense or the preterite)):