You can wire money to your broker, the money should be available that day if you do it early enough. If you sell a stock you have to wait 3 days before you can use the money.
If you buy a stock you have to wait 3 days before you sell it. If you sell it before the Trade+3days you can be put on a trading restriction for 90 days... I know did it, but it was worth it.
I was in a pump and dump, when I realized it was I bought more on the dip and sold the next day for even. But since my last trade did not clear 3 days before I sold it, I was restricted for 90 days. No big deal you just have to plan the money you need for a trade 3 days in advance if you don't have any funds available.
God Luck, ... Why Scottrade? What made you decide to go with them?