D&D FAQ said:You can make a long jump as part of a charge. You must
still follow all the normal rules for making a charge, such as
moving in a straight line on the battle grid.
. . .
Making a high jump as part of a charge is trickier. It’s hard
to imagine a significant high jump that doesn’t change your
direction; after all, you’re now moving vertically rather than
laterally.
. . .
2nd Ed Paladin said:There is also the feat in Complete Adveturer called Leap attack which requires a jump on a charge so, yes you can. The feat causes a multiplication of power attack to *3 on 2 handed weapons and *2 on one handed.
SRD said:Action: None. A Jump check is included in your movement, so it is part of a move action. If you run out of movement mid-jump, your next action (either on this turn or, if necessary, on your next turn) must be a move action to complete the jump.