MyFishFinder.com Just like iceshanty but warmer
Navionics boating USA . missing some lakes ,But it works on your phone with your phones GPS . hard to beat for $10 .
If you have an iPhone I like the app "Aqua Maps Maine" for $3.99. It has many more Maine lakes than other map apps I have looked at. It works off line so it saves battery and data charges. There is a web site that you can preview the lakes that are available before you commit to buy. I also use a standalone GPS receiver, Bad Elf, that improves accuracy and saves battery. I've been very happy with this set up for ice fishing.
Fishidy also has some decent maps for lakes that navionics doesn't cover. Not as detailed as navionics but still a lot better than the old ifw maps.
Just actually downloaded that app last weekend, so far it looks like it has some great info and most lakes are on there. Haven't tried it in a spot without service yet though to test if I can still get the maps