Since i'm going to join the Army mid-2009 to become a Ranger, i've decided to bulk up to 190 then cut to 180. I'm 5'9. However I do want to continue my Martial Arts training, so i'll be dropping my practice EXCEPT for Iron Palm/Makiwara training. Now my body will have to adjust to the new weight correct? What do you guys think.

Bulking then cutting is a dreadful idea, and is only a short term strategy used by bodybuilders (in fact, most top level BBers dont even do it anymore).

Bulking requires a 'shotgun' approach to nutrition, where, rather than give the body specificaly what it needs, you just throw energy into it and hope that some of it 'sticks' as muscle. In the meantime, you just get fat.

Cutting is merely the process of undoing the damage you have done by bulking. During this process, you not only remove the excess fat, but also catabolise a fair percentage of the muscle that is buried underneath it.

Net result: you end up weaker and with a slow metabolism, and with no further muscle growth than if you had done things properly in the first place.

Hey, you asked.

Agreed; not worth it. Remember, bulking up fast may see you gaining unwanted fat and we all know that it is easier to put fat on then it is to take off. You want to way more then you have to do it gradual by gaining muscle, eating right, resting properly, drinking adequate amounts of water; doing it right.

Is it possible to lose fat n gain muscle at the same time?

yep

bulking is old school. the "shotgun" method that Cord was talking about is how they used to do it and is incredibly unhealthy, and incredibly difficult w/o drugs, or at least tons of money to invest in diff supps. there are modified "shotgun" type cycles now that are in 4 or 5 week periods, where you bulk for 4-5 weeks, then cut for 4-5 weeks, and then go back and forth between those. best way is get your diet nailed in. once you get a diet nailed in, then figure out your metaboic rate, and go slightly above it. this will help you bulk up and not get all the unwanted body fat. you will also need to train for size if you want to put on muscle. there are several ways to put on size and they all work. Time under Tension is one tried and true hypertrophy method, as is higher volume workouts like GVT, but make sure you find a very balanced program if you go high volume. EDT(escalating density training) is a new technique that is supposed to pack on size quickly. WS4SB I has a great hypertrophy template w/ lots of room for sports training. it is geared towards athletes after all.

bottom line: eat right, don't go on a bulking/cutting tangent, and find what hypertrophy method works best for you.