I have friends who work at survey companies and I have interviewed with a couple... Basically if you are interested now, you are already too late. The "survey season" starts in late August to early October and lasts until about April or May. This isn't for all of the survey companies out there, but this is how most seem to operate. For these companies you can expect months straight on the road living out of a suitcase and mediocre hotels. Not a bad gig if you are single and want to see the country. Otherwise, I would think really hard about it.
And there are some companies that do aerial surveying year-round but they tend to operate different equipment than most of the seasonal survey companies. Most seasonal companies will have you flying in C172s and maybe some 182s. Most of the salary year-round type companies will have you flying anything from C172s and C210s to Barons and Senecas. Some even fly Turbine aircraft like King Air 90s and Cheyennes.
Most of the companies that do the seasonal work pay a little better as a general rule of thumb but you are on the road the whole entire time pretty much. And then when the season is over you are out looking for a job again. The good news is, if you have low total time (less than 500TT) a lot of the seasonal companies will give you a shot. Most of the salary survey jobs require at least 700 to 1,000TT and many of the ones that fly turbine require something like 500+ ME time. As far as pay, one company I interviewed at said that including per diem, total pay for about 7 months of work can be anywhere from 45,000 to 60,000+. Obviously, when you have to pay for a hotel/rental car/food that eats into that sum pretty quick. Others that are salary full-time positions usually start around 25,000 but they pay all of your expenses when you are on the road. I know of a couple that will also offer something like a 3,000 bonus upon completion of contract (usually 18 to 24 months). Hope this helps.