The tiny, roughly 1 sq km island is connected by a concrete bridge with the mainland and is said to be crowded by 16000 inhabitants, most of them living in shacks with dismal sanitary conditions.
Ilha can easily be reached by road from Nampula. If you're driving follow the road towards Nacala, and turn off at the signpost for Ilha de Mozambique (which is in Monapo). It'll take around 2 hours and the road is good. When you get there you'll need to cross the causeway which costs about Mts 5,000.
If you're taking a chapa they leave from Ave de Trabhadores in Nampula near the railway station and cost Mts 80,000.
Ilha's is fairly tiny and you won't have any trouble walking around it - it's about a 20 minute walk from end to end, and only about 3 blocks wide. Gabriel's has bikes you can hire for the day.
Everywhere. Ilha's a magical mix of old Portuguese and old muslim architecture. It basically divides into two halves - the old Stone Town in the north and the "Reed Town" in the south which is set down from the main streets.
The '''museum''' is in the old Palacio Govierno, a big red building up in Stone Town. In the same building is a tourist information office that sells really good street maps and has all sorts of other information about the various restaurants and pensaos on the island. It's well worth heading here as soon as you arrive.
Also worth a visit is the '''fort''' at the northern tip of the island, which contains the '''Church of Nossa Senhora Baluarte''', almost certainly the oldest surviving European building in the southern hemisphere, dating back to 1522. Be sure you pay the right attendant, or you will have to pay the entrance fee twice: Ask for a entrance ticket, if you don't get one, don't pay.
There's a '''dive centre''' at the northern end of the island just down from the fort, but ask a lot of questions, and think twice if you aren't an experienced diver yourself.
You can take '''boat trips''' or just '''laze on the beach'''. If you're feeling adventurous take a dhow over to the mainland at Chaga or Mossuril and explore along the coast there.
There aren't that many restaurants on the island, with '''Reliquias''' and '''Escondidinho''' heading the list up in Stone Town. But you can find a number of local places serving fish and rice or chima.
The cheapest option is the '''camp site''' on the mainland next to the bridge. Self catering is possible from the nearby shops. $4/person.