Uploading proofs to mpix

Hello all, i have been working on my photography lately and am going to be doing a proof set for my friend. A little background, i was asked to shoot her wedding and then she told me she couldnt afford me and had her cousin shoot it. I still brought my camera and shot and i think i got some nice images. What i am going to do is print out about 50 or so 4x6's and give it to her for her wedding gift. I have edited them using Adobe Camera RAW to get the colors and exposure right. As being a novice with printing, i have been doing some reading and everyone says make sure to sharpen as the last step. How do you guys do this? Sharpen through photoshop with filters, or doing selective sharpening? I would like a few pointers on this.
Also, when i try to upload the files to mpix they take FOREVER, running almost 7mb per file. How do you guys recommend to turn this down? I dont want to loose quality, but i know i dont need it that big. Any help would be GREATLY appreciated. Thank you very much!

-Bryan

Is there anyone that can help me out here? It is getting kinda buried in here

To print at 4x6, you can use the Image/Image Size function in Photoshop, set the dimensions you want (in the lower panel) and set the Resolution for a high quality, typically 300 pixels/inch. Then make sure the Resample box is checked.

Note that this will in fact "shrink" your image in terms of resolution and so it won't be suitable for a large print, but it will result in a smaller size file. It will be larger than a Web-viewing size, though.

After resizing it you can sharpen the resulting image for final printing -- how much is a matter of taste and of the actual subject/contents of the image so you may need to try a test batch to ensure that things come out good.

Thank you so much. I also just found the sharpening tips, tricks and FAQ so i will read through that.