Ok i found a way to dual boot meego 1.1 and maemo WITHOUT flashing maemo!
What you need BEFORE doing this tutorial:

• The repository of extras-devel
• A MicroSD card with 2Gb or more!! (class 6 is advised due to performance issues in Meego)

Secondly is to download this file:

• meego-handset-armv7l-n900-final-mod-1.1.0.0.20101101.3-mmcblk0p.raw.bz2

From this site:
http://tablets-dev.nokia.com/meego-codedrop.php (you need to input your IMEI to download)

Then after the download is done, extract the file using Winrar or 7zip (google for this two programs)
You will see a file with this name:
meego-handset-armv7l-n900-final-mod-1.1.0.0.20101101.3-mmcblk0p.raw

After this download this program:
Win32diskimager (CLICK HERE TO DOWNLOAD)

After this open win32diskimager and HIT the blue icon and open the folder where you extracted the file: meego-handset-armv7l-n900-final-mod-1.1.0.0.20101101.3-mmcblk0p.raw

After this start typing the name of the file until you can select it from the list that appears!



After the file is selected,
select the letter of the MicroSD card where the meego image is going to be written:


And after all that is done hit: WRITE



You will see that a confirmation will come up and you can hit YES!

It will take some time to write the image to the microSD!

After the image is written to the microSD you will need to download uboot-pr1.3

Go to the file manager and search for uboot-pr13 and install it!



You can download it via x-terminal using this:
After it is installed you can reboot and it will reboot in meego!

Have some patience because meego will take some time to start!

After you experience meego and if you want to remove it just run this command in x-terminal:
And format the microSD!

Pros of this tutorial:

• You will have the opportunity to experience meego;
• Dual-boot to have the opportunity to exchange between two OS's
• Experience something new!

Cons of this process:

• Meego isn't finished by 100% so expect some bugs;
• I won't help with meego bugs because you are experiencing something that is in a beta stage and NOT A FINAL PRODUCT;
• VERY SLOW but still atractive though :P

Have fun!

Edit:

To boot maemo instead of meego:

Hit any key to stop the N900 from booting into meego and write this in the console:
And it will boot into Maemo

(thanks DrWilken for the tip!)