In reply to DomBPT1:
Not really any need of rope as the glaciar has little to no crevasse dangers... In "el paso de Mahomma" you may want to set a rope up if you're not comfortable with that amount of exposure though...
I'd recommend going up the glaciar de la Maladeta and climb the Maladeta, traverse the ridge and rappel down to the glaciar del Aneto (there's your excuse to take a rope), traverse the glacier and finally cross el paso de Mahomma up to Aneto. That way you'll take to very nice summits for the price of one and you won't feel bad for carrying the rope if you don't feel you need it at el paso de Mahomma. Furthermore, Maladeta has probably one of the most beautiful sights in all of the Pyrenees...
Depending on the amount of snow you could also forget about el paso de Mahoma, bivy in Collado Coronas and climb up the Corredor Estasen: a nicer and least frequented route.