Editor's Note: The following is an excerpt available exclusively at TheStreet.com from a story originally published by Investment U.After four years of getting pushed around by the euro, the dollar has been strengthening in 2005. In fact, it's hovering close to the two-year highs made last month. And most likely it is not over. But how can you invest in or trade that belief? How does the average trader or investor buy and sell dollars? Let's look at the most common and accessible ways to invest in the dollar, and which instruments might be the most useful for your account. Whether you think the dollar will go up or down, if you want to trade or invest in it, you have to have something to buy or sell. You could always run down to a bank or an international airport and exchange all your euros for dollars, or vice versa. But as anyone who has traveled to a foreign country knows, the transaction fees charged by banks or currency exchange kiosks are huge! So let's look at some more practical alternatives, ranging from the futures and forEx markets to several available mutual funds.