Making good progress
Have all my wires out and working off the probe in 2 cars.
But have a couple of questions.
1.Should i stick a resistor between the arduino and the R/C board just to make sure I am not running too much current(even if the voltages match)? (wanted to check before hooking it up in case this is why i blew the first one up).
If you are concerned, then go for it (it can't do anything but not work - in that there won't be enough current to activate the transistor) - but if you traced your lines right, you should find a resistor before the base of the transistor involved for the action; note the schematic on the datasheet. Something similar should be on the board. The only difference might be if the chip on board is being run at a lower voltage than the Arduino, then on-board resistor might be sized for that voltage for the current needed (measure the resistor, measure the voltage - then work out the current; once you know that, then knowing the HIGH voltage of the Arduino is 5 volts, you can figure out the needed resistor size for the Arduino at the current needed (don't exceed about 20 ma!) - so if currently there is a 400 ohm resistor on-board for the RX2, but you figure the Arduino needs a 500 ohm resistor, then you just need to add a 100 ohm resistor in front of the first - note that all of those figures are pulled from my rear - you need to measure it all yourself!).
2. Sometimes my solder doesn't seem to stick to the board very until dry. Is there a reason for this?
What do you mean by "until dry"? The only possible reason why the solder might be an issue (I think) is if you are using a different solder from what the board was soldered with (ie, you are using lead-free and the board was done with leaded solder, or vice-versa; note also that lead-free solders have a higher melting point than leaded solders, so it could be technique or your iron; likely technique though, if this is the case).
3. Any tips on how to get a third hand. Wire + solder + iron = 3 and i only have 2
. I have tried a number of ways including sticking the wire down in place before soldering but I keep thinking there must be an easier way.
Well, here in the States I use leaded solder, so I have an extra arm growing out of the side of my torso...
Seriously - get some electrical wire like used for house wiring (large guage, single solid core wire) - cut a few lengths of about 10 cm or so (gauge for yourself what you need); on one end, crimp a largish alligator clip; nail or screw the other end to a board. Voila - el-cheapo "third hand". Not quite as good as a PCB vice, but serviceable for many jobs!
4. With a 4WD car am I going to need more than 4 arduino ports(not sure if that is what to call them) than you need for the standard car?
What kind of 4WD car? If it is a hobbyist 4WD car (like a Traxxas), then no - you will only need two pins: one for the speed controller, the other for steering; unless you have extra accessories and such; basically you need one pin for each servo or ESC (electronic speed controller).