Like a lot of people, I have a mobile phone / cellphone but I also have a landline at my office that has is just easier to use for long conversations, or times when I need to use my desktop computer while calling someone from the office.

I also love to use Remember the Milk to remind me of those phone calls. So I have a location called "Phone". That way, when I'm near my office phone, RTM will show me any calls I need to make that could be made easily on my office phone. Those tasks also show up if I select "Nearby", so I'm reminded either way.

If I'm out and about, I can just tap "phone" location on my iPhone and I'll still see the same list of calls, just in case I feel like checking off a couple of urgent ones on my iPhone.

That works brilliantly for me, because I tried locations instead of just the tags as usual. Give it a try!