Here's how I would dive different places in the Philippines if I have 6-8 weeks and I'm budget conscious. This is based on avoiding domestic plane travel which is very strict about luggage allowance, as much as possible. Also bear in mind, although there are pockets of big fish/pelagics in the Philippines, the diving is mainly macro or muck diving (you will love it so my suggestion- get in to underwater photography fast).
IF YOU ARE FLYING IN TO MANILA- try to arrive during daytime. Have your resort pick you up from the airport upon arrival so you don't have to spend paying for a hotel in Manila. Go to Anilao, Batangas. Suggested dive resort- Dive 7000 in Anilao. Stay here for a week. Other suggested resorts (also in Anilao) - Club Ocellaris, Dive Planet. Transfer to Puerto Galera, Mindoro by a bus ride to the Port of Batangas and then by ferry to Puerto Galera. Check with your resort in Batangas for info about the transfer. Suggested resort in Puerto Galera- La Laguna Beach Club and Dive Centre, Puerto Galera, Philippines. Stay about 5-7 days. Return to Manila and consider Subic as previously mentioned by another member. Or go to Donsol, Sorsogon (for the whalesharks, snorkle only) by plane ride to Legazpi City, Albay (& take a 1 hour taxi ride to Donsol). After you had your fun with the whale sharks, directly go to Ticao Island for the mantas via outriggers arranged by your resort in Ticao. Resorts in Ticao= ticao-island-resort.com and STEADYEDDIEDIVE.COM (stay about 5 nights). Return to Manila and take the interisland ferry or flight to Cebu (there are flights from Manila or Legazpi to Cebu).
IF YOU ARE FLYING TO CEBU-stay at the Waterfront Hotel, Mactan (right across the airport; walking distance) IF you have to stay one night before going to your resort. Go to Malapascua, Cebu for the tresher shark/manta/Dona Marilyn wreck/Gato Island/mating mandarin fish, etc.; stay about a week. Suggested resort= Malapascua Exotic Dive Restort. Then go to Moalboal, Cebu by bus (whale shark?) and dive for about 5 days. Travel by bus or transport provided by your resort to Santander, Cebu for crossing by ferry to Dumaguete, Negros and stay for about a week in one of the resorts in Dauin (Pura Vida, Atlantis, Bahura). Don't miss Apo Island which is a 30 minutes away by your dive boat and the pier dive in Dumaguete. Take the fast ferry (SuperCat - SuperFerry Travel and Leisure - Aboitiz Transport System Corporation or Ocean Jet) to Tagbilaran, Bohol and stay/dive in Panglao, Bohol for about a week. The other option while in Bohol is to go to Cabilao for about 5 nights (Cabilao Beach Club, Resort) or to a resort in western Bohol (do a google search for this resort). Then take a ferry ride to Cebu City for your flight out of the Philippines or go to Manila directly from Tagbilaran City by plane.
You can only dive Tubbataha by liveaboard (limited dive window because of winds). You have to take the plane to Puerto Princesa, Palawan to get to the live aboards or take the liveaboard in Batangas during their transition trip to Tubbataha (expeditionfleet.com). Befor/after Tubbataha, you can do your wrecks in Coron, Palawan.
I don't have any business relationship with the resorts that I have mentioned.
Credit cards and travelers checks are only accepted in the big cities like Cebu and Manila and most resorts will apply a 6% surcharge if you use them. Get some local currency upon arrival in your airport of entry.
Rolando