An LLC would file IRS Form 8832 to elect to be taxed as a corporation. Beyond that, you would be filing an annual corporation income tax return (Form 1120) instead of just attaching a Schedule C to your 1040 individual income tax return. State tax filings might be a little different also, so you'll want to check with your state's department of taxation for information.

Obviously, taxation is different with a corporation and things can get complicated, so the best thing would be to consult a CPA for guidance/assistance. There might be some tax implications you haven't thought of.

As an example, assets can generally be transferred between an LLC and its owner with no taxable consequence (because a single-member LLC is disregarded for tax purposes), so when you want to put something into or taking something out of the LLC, it's not such a big deal relatively speaking. But transferring assets from yourself to a corporation (or an LLC that is taxed like one) might result in a taxable gain to the corporation. So talk to a CPA to beef up your understanding of the tax implications associated with an LLC that is taxed as a corporation and the things you'll need to do that you might not otherwise have to with an LLC that is taxed like a sole proprietorship.