Banosby said:
Also, can I use trip attacks as part of a flurry of blows? That is, can I attempt two trips in own round against two different targets with the flurry? Can I flurry and have the first attack be a trip and the second a normal strike? If so, do I have to declare that the second will be a normal strike before making the trip attempt, or can I wait and decide if I want to try another trip or make a normal attack until after I see if the first trip worked?
You can only use a trip in a FoB if you are using a special monk monk weapon that allows you to make a trip attempt, i.e. the kama.
The reasoning is that an unarmed trip attempt requires an 'unarmed melee touch attack' to make the grab, and this is not an 'unarmed strike', which is the only unarmed option available with a FoB.
So, to address your specific questions:
> can I attempt two trips in one round against two different targets with the flurry?
Yes, if wielding a kama.
> Can I flurry and have the first attack be a trip and the second a normal strike?
Yes. The first attack would have to be with the kama, and the second attack can be with either the kama or an unarmed strike. And don't forget that if you have Improved Trip that you get a free attack on a successful trip - but I'm unsure whether the free attack from Improved Trip would have to be made with the kama, or could be an unarmed strike.
> do I have to declare that the second will be a normal strike before making the trip attempt, or can I wait and decide if I want to try another trip or make a normal attack until after I see if the first trip worked?
You resolve each attack individually, declaring the target and method of attack as you go to resolve each attack.
For example, as a 7th level monk with FoB, you get 2 attacks. Your action for the round is FoB (a full round action). You use your kama to trip the goblin and with the free follow attack you elect to use your Stunning Blow ability to take him out of the fight for the round. Now you look around for your next target, you see that the hobgoblin need only take a 5ft step to unleash a full attack on you (assuming he gets multiple attacks), so you decide to take a 5ft step away and throw a shuriken at him to soften him up.