This is a complicated glitch I discovered a long time ago.
You need to be at the rank of capo (3 stripes) and be on the mission "order to kill" (in which you kill monk)
You will need a full hit squad gauge, enough money to summon the hit squad as many times as you want to duplicate it ($5,000 per duplication), a way of killing yourself (I.e. Molotov cocktails), and a crew member (the rank 3/3 stripe crew member is the only one I tested). Here is how to work the glitch:
Summon your hit squad and have your crew member with you. Start the mission by going into the blue circle by the bowery hotel. Talk to monk, then kill yourself, either by blowing yourself, burning yourself with one of the molotov cocktails, or possibly using an explosive barrel. When given the option, choose to start over from the checkpoint. When you appear back in the alley, your hit squad meter should be full. If it is, quit the mission, and then dismiss your hit squad. Enter the blue circle again, and, after talking to monk, check to see if your crew member is there. If he is, you have successfully set up the glitch. To duplicate your crew member, kill yourself, and choose to start over from the checkpoint. Each time you kill yourself (in mission), another crew member will appear. You can create as many as you like, and they will still be present if you quit the mission. If you quit the game and return to that file the duplicates will disappear and you will have to repeat the glitch (even if you saved while you had the duplicates with you). Next, how to get a lot of hit squad members. Once you have set up the glitch, (see above for instructions on how to set it up), kill yourself, choose to start from the checkpoint, then quit the mission. Summon your hit squad once you are out of the mission, then re-enter the blue circle. After talking to monk, check to see if your hit squad is there. If it is, kill yourself and choose to start over from the check point. Your hit squad meter should be filled again. If it is, quit the mission. Dismiss your hit squad (the glitch should make it so they don't leave, and instead remain part of your hit squad), then summon your squad again. You should now have 7 or 8 hit squad members. If you do, and want to create more, enter the blue circle again, talk to monk, kill yourself, and start over from the check point to refill the hit squad meter. Quit the mission, dismiss your hit squad, and summon it again. Repeat as many times as you like to create more hit squad members.
IMPORTANT: this glitch CAN freeze the game. If the game freezes, unplug the Wii and then plug it back in.
I hope you all enjoy this awesome glitch!
~actionreplayer~

I discovered this bizzare easter egg(?) recently.
You need to have the rank, "Don of NYC" to do this.
Go to either the bowery hotel, the savannah hotel, the elegante, the st sebastian hotel, or the george hotel, and there should be a hooker inside with the "crew for hire" symbol over her head. Each one charges a different amount, and all have special weapons.
This may not work for some of you. On a copy of the character I discovered this on, this did not work, so for the record, you may need:
50 hours lifetime on the character,
$3,000,000,
And/or 100% game completion (not according to the career progress sheet, but according to the criminal progress sheet in tom's report).
Sorry if it doesnt work for some of you.
~actionreplayer~

If you are always running out of ammo or health check out these cheats. (Hint: These are NOT infinite ammo or health)

To refil your ammo pause the game and enter: left, minus key,right, 2, right, up. (on the direction pad, not the numchuck.)

To refil your health pause the game enter: 2, left,2, right, minus key, down. (also on the d-pad.)

These codes do work but I think they have a 5 minute lockout. If you do either code it wil not work again for another 2 or 3 minutes.