The Find a sound website will find a wide range of suitable sound effects.
Talking Products has a huge range of talking tins, labels, badges...even scrabble tiles!
Audacity is a free sound editor. Great for podcasting and editing sounds.
Try this sound pelmanism quiz......
This is fantastic quiz on animal noises from Kidsplanet!
Brilliant, royalty free sound effects site. Just type in the sound effect needed...and a selection appears!
Great database full of free soundclips.
This is my sound presentation in Smart Notebook