[myTouch 3G, Magic Android Development] Mr. Nefarious:
Staunty: I was in your position yesterday. I'm thinking about making a write up for noobs solely about partitioning, simply because until you do it, the language and way to do it was extremely hard to find. Here is how I did it:

I could not get ADB to work at all, not sure why but I get an error every time I try to mount or find my device in console, I've heard of ADB problems on windows 7 and even tried a fix to no avail. Realizing ADB was out of the question, I needed to format the SD card outside the phone. I did not have a card reader, so I drove to best buy and for 19.99 purchased a card reader for my pc. It is by rocketfish and comes in a red box in case you go my route. Thankfully it reads micro SD cards WITHOUT a converter to normal SD. If you have all the materials, time to format the card.

Because Android needs a linux-swap and EXT2 or EXT3 partition for what we're doing, windows can't format the card correctly without using ADB. The workaround is to use linux. You don't have to install linux, you can just burn it onto a CD and boot up with it for a 1 time use to format your SD card. If you don't have a CD burner like myself, you can use a USB drive. I went to www.linuxmint.com and downloaded linux mint for free. Mint is like ubuntu but extremely user friendly. It comes with Gparted, the partition editor. In mint, there is a search bar right in the program menu. Search for partition or Gparted and it will show up. Put your card into the card reader. Select your SD card from the drop down window in Gparted. Look for the "device" with 3.69gb of available space, thats your 4GB SD card. Right click each partition and select "unmount". Once your entire SD card is "unallocated" you're ready to divide up your memory card into partitions.

You stated that you have a 4 gig card. I'm assuming it's the stock class2 mytouch card. Thats the card I'm using as well, so I'll give you my numbers. Just an FYI, I decided to use a very large EXT3 and very large swap as I've heard not having enough swap can lead to lag so I decided to be overly generous, you can change these numbers to whatever you want. I also left some space unpartitioned just to be on the safe side since this was my first time partitioning the card.

Right click on Unallocated and select new at the top. We're going to do your FAT32 first. In the middle box on the left that says "Size" type 2900, I believe it asks you for the # in mb. If it asks for GB just type 2.9. On the lower right hand side, select FAT32 and then less ok. The second partition we'll make is an EXT3 partition. Most other methods can't directly create an EXT3 partition, however Gparted does let us do this. Lets take advantage while we can. Right click again on unallocated and fill in 575 for size. This time select EXT3 from the drop down menu. Hit create. Last and certainly not least, our Linux-Swap partition. Create a new partition again, fill in 225 for the size and select Linux-Swap for the partition. After you've created all 3, click the green check mark above the white partitioning area. You will get a message that all data on the card will be lost. Click yes. Wait for the computer to create the new partitions on the card and then viola, you've partitioned your SD card without ADB. I apologize if any of this seemed long winded or condescending, however I simply wanted to write out every possible step because I know at one point I really wanted to see something as step by step as this.