We moved across the country (and away from friends and family) when ds was 2.5. Here's what we did.
1) Didn't really talk about it until the month before we were to leave. I started packing stuff up at that time and he certainly noticed.
2) Took a lot of pictures of him with family members, friends, and at favorite places and put together a collage to hang on his new bedroom wall.
3) Packed his favorite toys and stuffed animals at the last minute. He helped pack them and said "Good-bye [toy]!! See you in [our new home]" to each toy. I felt it was particularly important that he help pack his own things so he would know what happened to each toy.
4) Allowed him to pick one special stuffed animal to keep with him and not get packed up with the others.
5) Talked up our new state/town and how much fun it was going to be to live there.
6) When we arrived he helped unpack his things and set up his new room. He had a lot of fun doing this.
7) ASAP after arriving we went for a walk around town and saw the playground, the pool, the library, the river that runs through town, daddy's workplace, all the cool, fun stuff. We visited the library and park asap as well in hopes of meeting other kids.
8) For the first 6 months or so ds would say, occassionally, "I miss Oma." or "I miss Auntie." and we would talk about how we miss everyone. We wrote letters and drew pictures to mail home. We also traded pictures over the internet, which helped. This did, eventually, stop and I soon had to beg him to draw a picture to mail to Grandma.
Ds adjusted fairly quickly to our new surroundings and I think it was harder on me than on him. Especially once he got into a routine and met some other kids to play with it was smooth sailing.
Good luck! Kids are fairly adjustable, I'll bet your dc will be just fine.