I have next to my front door, two light switches. One controls my porch light and the other controls an outlet not far from the switch.

I want to wire the outlet to remain constantly on (not operated by switch), and I plan on adding a room light to the "old" outlet switch.

I understand how to wire the new light into the existing switch which currently operates the outlet, but I do not understand how to convert the outlet to a constant feed from the switch box?

You have a hot to the switch already. Keep all the whites connected. Keep all grounds connected. Connect the hot black to the black outlet wire and pigtail a 6" black wire to that and wire nut together. Put the pigtail lead onto 1 side of the switch and the new light black to the other side of the switch. Outlet should be hot and switch controls light.

Can't really tell you much until you tell us the colors of all the wires that pass through that switch box. In some cases you can't install that new light but we sure can get the outket to always be hot.

You'd need to tell us exactly what wires are at the switch and at the receptacle, and how they are all hooked up.

This can be wired two ways and both are very common. Each requires a different re-configuration.