Ok, my amp has been losing volume when it gets too hot and squealing uncontrollably at low levels of gain.
I am going to replace the tubes to stop this madness and I have never done this AT ALL before.
I thought that starting with the preamp tubes would be the best bet for fixing these problems, but I need some help.

I asked dougstubes.com and they recommended me these tubes in these postions:

1st :Electro Harmonix 12AX7-EH
2nd: Tung-Sol 12AX7
3rd: Sovtek 12AX7-LPS

What are the procedures I need to take to do this without any problems? Do I just take them out and put the new ones in and that's it? Is there anything I should know or do beforehand?

I know how to take them out and stuff, I have fiddled around in the innards of my amp a few times, but I am not sure the procedure for putting new tubes in.

Also I have read a lot about biasing and whatnot and I am not sure if my amp auto bias. I have never seen a switch or anything that might be what you bias them with on my amp.
And my amp is in my sig BTW.
Ok, I don't think there is a 3 pin connector anywhere on my amp, so I don't need to bias my Power tubes? also is spraying the pins with contact cleaner necessary

EDIT: I agree, that guy could probably be a serial killer.
Just make sure you don't touch the tubes with your bare hands and be gentle when you put them back in.

Oh, and watch our for capacitors, those are what might give you a near/fatal shock.

Depending on your amp, you will have to rebias -- check with your manufacturer.
eurotubes has a re-tube kit specifically for the crate v3112 which is the same as the palomino v32. i just re-tubed mine with the high gain kit for about 85 bucks. sounds awesome. No bias needed as he provides a quad set of EL84's.
Crate V3112
Mesa Mk IVB

Ibanez SZ320
BC Rich Mockingbird Special X
Michael Kelly Patriot Custom

Too Many to list.