I think at some point in every washing machine's life it starts to smell, regardless of how many times you clean the rubber seal, because it's the bits that you can't get to that stink. So, before you go out and buy a bottle of expensive, nasty, chemicals give these recipes a try:
For areas you can see:
For areas you can't:
2 cups white vinegar
1/4 cup baking soda
1/4 cup warm water
10 drops of tea tree oil (for extra anti-bac power and nicer smell)
Firstly you need to clean the areas you can reach using a cloth and kitchen spray. If you have a a particularly mouldy rubber seal and need extra cleaning power, pour some neat vinegar on the seal and leave for a minute or two before wiping. Don't skip this step as the seal holds a lot of grime.
Next mix the vinegar, baking soda, warm water and tea tree together in a bowl, and pour into the detergent draw of your machine. Run the hottest cycle and voila! Smell-free laundry next-time you wash.
Give it a go and let me know what you think.