Since you are looking at saving $25,000 you can afford to spend something on tools and learning.
You may find that you can use a lot of what is already in the walls if you don't plan to tear down the wall material.
I suggest that you get a permit immeditely because the new 2008 code requires Arc Fault Circuit Interrupters in every 120 Volt, 15 or 20 Amp residential circuit. They are very expensive, unreliable, and a pain in the butt.
Buy a copy of the applicable code, preferably with the notes. You should also get a good manual on residential wiring.
Read some of the material on
www.mikeholt.com . They won't help non-professionals but you can learn a lot and you may learn how you can ask questions in a way that won't make it look like you are an amatuer.
If you don't know how residential systems work, spend some time learning about how 120 and 240 Volt circuits work in a residential installation. Learn it until you can do it without thinking about it.
If you are living in the home while doing the rewiring, then you can do it is pieces.
At some point you will want to replace the service. That is possible but can be difficult for an amatuer. I have posted a couple of descriptions in this forum about how I planned and did mine with minimum interruption of service.
You need to do a lot of planning before you start stringing wire. It will save you a lot of time.