We just got back from a trip with our six week old. It was great - hot, so we spent a lot of time at the hotel by the pool, or indoors on air conditioned rides or at the baby centres - tried them all - really great - the best one is at MK. Keep baby hydrated - easy if you are breastfeeding - don't try to do too much or overdo it at the parks. Ask CM's for help if you need to find a quite place to feed the baby. Having family around helped too, they took DD off when baby and I needed to rest or escape the heat. Missed doing some stuff with her but still had a wonderful time. Sunscreen is probably not going to work on a three month old - ask your pead. We used thin knitted cotton blankets to shade baby instead which were nice because they still let the breeze through. Make sure you stay hydrated too - take LOTS of water with you to the park - a bottle an hour would be a good estimate. HAve a wonderful time. Congratulations!
leighe - can you get DH to reconsider at this late date? I just know I would have been miserable without my little man.