JOEL - As far as I know the Church has no "official" position regarding short-term stock market trading. The scripture that comes to mind is;
"For behold, it is not meet that I should command in all things; for he that is compelled in all things, the same is a slothful and not a wise servant; wherefore he receiveth no reward." (D&C 58:26)

I am sure church leaders might have their own personal opinions on investment stategies, but there are some of them who would not be as well off as they are today, were it not for their wise investments in the stock market. Leaders have cautioned that we should be responsible and careful how we handle our investments and that we should not allow ourselves to get into unnecessary debt. I do agree that trading on the stock market is a bit of a gamble if you don't know what your'e doing.

The Church's attitude toward gambling was set forth in the following statement by President Heber J. Grant and his counselors in the First Presidency on September 21, 1925:

“The Church has been and now is unalterably opposed to gambling in any form whatever. It is opposed to any game of chance, occupation, or so-called business, which takes money from the person who may be possessed of it without giving value received in return. It is opposed to all practices the tendency of which is to encourage the spirit of reckless speculation, and particularly to that which tends to degrade or weaken the high moral standard which members of the Church, and our community at large, have always maintained."
Improvement Era, vol. 29 (September 1926), p. 1100.

So as long as your trading activities can be conducted in a manner that does not contradict the advise given above, there should be no problem pursuing this type of investing. If done wisely and patiently over time stock market trading will almost always bring back returns that will eventually increase the value of your investments. The only problem I see is when people get greedy and go into debt by borrowing money for trading or if trading becomes a chronic addiction that causes the person to consistantly lose money and time spent with his family.

N. Eldon Tanner once said;
"Investment debt should be fully secured so as not to encumber a family’s security. Don’t invest in speculative ventures. The spirit of speculation can become intoxicating. Many fortunes have been wiped out by the uncontrolled appetite to accumulate more and more. Let us learn from the sorrows of the past and avoid enslaving our time, energy, and general health to a gluttonous appetite to acquire increased material goods."
(N. Eldon Tanner, Ensign, June 1982, pp. 2-7.

As members of the Church, we are encouraged to save and invest money wisely. But the cost of unwise investments is not only financial; often those who get into tight financial situations reduce or eliminate tithing, budget, fast offerings, or other contributions as a way to get out of debt, and thus quickly lose needed blessings.
I think as long as we keep in mind the wisdom of the prophet Jacob, it is possible to obtain some form of financial security in our lives, regardless of how we do it;

“But before ye seek for riches, seek ye for the kingdom of God.
“And after ye have obtained a hope in Christ ye shall obtain riches, if ye seek them; and ye will seek them for the intent to do good—to clothe the naked, and to feed the hungry, and to liberate the captive, and administer relief to the sick and the afflicted.” (Jacob 2:18-19)