[Motorola Milestone Android Development] Lollipop_Lawlipop:
Ahhhh, although there are countless guides, since you asked so nicely...

1) Make sure you have ADB setup and working. Anyone with even attempting to meddle with Android should be familiar with how it works.

If you don't have it setup, get it from http://developer.android.com/sdk/index.html. Extract it to a location you can easily type by hand (eg. for Windows, directly to C:\) and run the SDK Manager. This will also depend on what OS you're running on. Consult the page for more info. Download platform-tools in the manager.

2) Using command line/terminal, navigate to the /platform-tools folder.

3) There are two ways to acquire the 10overclock file you'll need to change the clocks/voltage. One way getting the file directly off your phone. The other is to get the file from the update package you downloaded from nadlabak. To get this file, open the zip file, navigate to /etc/init.d/ and extract the 10overclock file. Skip to step 5) if you are doing it this way.

4) To get the file directly off your phone, using the command line, type in:

adb remount
adb pull /system/etc/init.d/10overclock

Note that if you're running Powershell, Linux, or OSX, you'll need to type:

./adb remount
./adb pull /system/etc/init.d/10overclock

5) Open the 10overclock file using a text editor that's not notepad. Something that can understand the world of Unix. For Windows, a good one for this is the free Notepad++. OSX and Linux users don't have to worry a thing. Text Wrangler or Text Edit does the job fine, as will gedit.

6) Time for editing! If you're only going to be playing around with clocks and voltages, these are the only lines you'll need to worry about:

echo 60 > /proc/overclock/max_vsel
echo 900000 > /proc/overclock/max_rate

#echo "5 900000000 60" > /proc/overclock/mpu_opps
echo "4 700000000 49" > /proc/overclock/mpu_opps
echo "3 500000000 44" > /proc/overclock/mpu_opps
echo "2 250000000 33" > /proc/overclock/mpu_opps
#echo "1 125000000 32" > /proc/overclock/mpu_opps

#echo "0 900000" > /proc/overclock/freq_table
echo "1 700000" > /proc/overclock/freq_table
echo "2 500000" > /proc/overclock/freq_table
echo "3 250000" > /proc/overclock/freq_table

I'll explain these lines part by part.

echo 60 > /proc/overclock/max_vsel
echo 900000 > /proc/overclock/max_rate

These two are the maximum voltage and maximum clock your phone will run at. If you're just interested in changing the max clock, these two values are it. The default are 900mhz/60vsel. Most phones can push to 1000mhz/60vsel. The easy rule to change the intimidating max clock value is simply think of the clock speed you want in mhz, then multiply it by 1000. So if you want 1ghz/60vsel, then you will change the lines to:

echo 60 > /proc/overclock/max_vsel
echo 1000000 > /proc/overclock/max_rate

---

#echo "5 900000000 60" > /proc/overclock/mpu_opps
echo "4 700000000 49" > /proc/overclock/mpu_opps
echo "3 500000000 44" > /proc/overclock/mpu_opps
echo "2 250000000 33" > /proc/overclock/mpu_opps
#echo "1 125000000 32" > /proc/overclock/mpu_opps

These lines are for clocks that the phone will scale down to. For our kernel, we can have 4 "levels" or slots for our phones to clock up and down from. In this case (default case), our phone will have 250mhz/33vsel, 500mhz/44vsel, 700mhz/49vsel, and finally 900mhz/60vsel. Note that you already set the max clock previously, so you do not have to worry about those anymore.

Chances are, you do not want to touch the clocks. Rather, you will want to change the voltage. This will be different from phone to phone, so do your own tests! Ignore the values that have been commented out - that is, the lines with the "#" in front of it.

For reference, my phone's values:

echo 60 > /proc/overclock/max_vsel
echo 1000000 > /proc/overclock/max_rate

#echo "5 900000000 60" > /proc/overclock/mpu_opps
echo "4 750000000 47" > /proc/overclock/mpu_opps
echo "3 500000000 33" > /proc/overclock/mpu_opps
echo "2 250000000 24" > /proc/overclock/mpu_opps
#echo "1 125000000 32" > /proc/overclock/mpu_opps

#echo "0 900000" > /proc/overclock/freq_table
echo "1 750000" > /proc/overclock/freq_table
echo "2 500000" > /proc/overclock/freq_table
echo "3 250000" > /proc/overclock/freq_table

Note that if you changed the clocks, like 700mhz for 750mhz in my case, you should also change the lines at the bottom.

6) Done? Remember to save your work. Push the file (and reboot) into your phone using the following lines:

adb remount
adb push 10overclock /system/etc/init.d/10overclock
adb shell chmod 755 /system/etc/init.d/10overclock
adb shell reboot

For OSX/Linux/Powershell:

./adb remount
./adb push 10overclock /system/etc/init.d/10overclock
./adb shell chmod 755 /system/etc/init.d/10overclock
./adb shell reboot

7) That's it! I've attached my own 10overclock file that has Feeyo's 'optimized kernel setting' and my own tweaked minfree values for reference (multitasking galore!).