Scrub and debeard the mussels.
Put them in a large kettle and add the wine.
Cover and steam for 3 to 5 minutes until the mussels open.
Take the mussels from the pot and strain the cooking liquid through cheesecloth or a coffee filter and reserve.
Set aside 12 mussels in the shell for garnish.
Remove the remainder from the shells and reserve the mussel meat.
Discard the shells.Heat the olive oil in a large saucepan or kettle.
Add the garlic and cook gently for 1 minute.
Add the tomatoes, anchovies, oregano, pepper and reserved mussel cooking liquid.
Cook gently, stirring often to break up the tomatoes and dissolve the anchovies, for 15 to 20 minutes until slightly thickened.
If the sauce is too thick, add some of the reserved tomato liquid. (The sauce can be made a day ahead to this point.) Meanwhile, bring a large pot of water to the boil for the pasta.
Add salt and the spaghetti and cook for about 9 minutes until al dente.
Drain well.Just before serving, add the mussels and parsley to the simmering sauce.
Cook for about 1 minute until the mussels are heated through.
Taste and add salt if desired.