My first suggestion would be to put it onto a nice parchment background. You can create your own with Gimp following the tutorial here:
http://www.cartographersguild.com/sh...ight=parchment
or just steal the one Del posted at the end. Or you can do a Google image search for blank parchment and you'll get a ton of images you can steal.
After you've got a nice parchment texture, open up your map, I'm going to assume you do this in Gimp.
Make sure you've got the layers dialogue open. You'll probably only have one layer there called background with your image on it. Right click this layer and go to -duplicate layer. It won't show any differently in the main window, but the layers dialogue will now show that you have two layers, both with the same thumbnail.
Now open your parchment texture in a separate window. First check that it is big enough to hold your map - the dimensions in pixels should be in the title bar of the two image windows so it's easy to compare. If it's not quite right then go to Image->Scale Image... Make sure you change the dimensions to pixels (in the drop down menu) then set it to the right scale to hold you hand drawn map. After it is the right size, use ctrl-A to select all and then ctrl-C to copy. You can now close the parchment image.
Back to your image. Create a new layer (the new layer button is on the bottom left of the layers window). Click back to the main window with your map in it and hit ctrl-V. This will paste your parchment into the layer. Now go to the layer dialogue and move it so it is beneath the layer with your map on it.
Select the layer with your map on it - should be the top layer of your set of layers now. Go to Layer->Transparency->Colour to Alpha.... Accept the default of white and click okay. Voila, you now have a nice hand drawn map on a parchment background.
Save this as a .xcf (Gimp's native format that preserves everything) before saving as a jpg and posting the results here.
The next step is to colour it, but I'll let someone else deal with that - if they haven't already done so by the time I post this!
Now select the bottom of those two layers - the one called background.