My mom's always been very stoic about the whole thing and has never let on that she's really upset, but I know she wishes I wasn't gone.... My mom's always been the "do what you really and truly want to do and I'll support you no matter what I think" type. But knowing that she misses me very much makes me sad and I do all I can to minimize the distance. What's helped:
- Sending little things - cards, trinkets, etc. via post
- Having a minimum of one phone call a week BUT making sure to occaisionally phone to ask her questions that show I still need her (e.g. I just phoned not long ago while I was baking to ask her how much a cube of butter weighed 'cause I was converting a recipe - that sort of stuff makes her feel needed AND makes it seem like I'm still close by 'cause I can just call at the drop of a hat for little things.)
- Sending lots of pictures illustrating that I'm happy and being looked after by dh.
- Encouraging her to send packages here (I know that sounds weird, but I know she actually enjoys packing up issues of People, cooking mags, etc. and going to the post office to send them - she's a regular at the counter - knows just how much weight she's allowed in an envelope, weighs it on the kitchen scale, etc.) I think it's a way she can still feel like she's looking after me to an extent....
Anyway, that's been my method and even though she misses me, I know it takes the sting out of it and now she even says "it's amazing how small the world actually is" - it's taken a while but I think she's truly OK with it now.... Good luck, trudif!!!