well, in brief ..
look around the main ogre site for blender .scene and .mesh exporters (i think they are in the tools section, try googling if not). those utils will export .xml files, you will also need the ogre command line tools to convert the xml into binary .mesh files. Look at the blender mesh export script for details of how to set this up automatically.
the post with a scene importer is here:
you need to export the .scene file, and each mesh individually ( personally i prefer to just do the meshes, and do the scene creation through python, which allows more control over when objects are spawned etc.). You'll have to UV-map your blender meshes to get textures to appear, if you do that, the exporter will create material files automatically for you, although you may have to edit by hand a bit (use notepad). The script will also export armature animations to a skeleton file, which also needs converting from xml to binary. you do not need to convert the .scene file from xml, it will work straight after export from blender.
theres a post in this forum with a link to a good .scene import script for pyogre, which will load the locations of your meshes into pyogre from your .scene file.
once all that is done, make sure your resources.cfg is set up correctly to match the folders of meshes / materials / textures you have created (Of course, make sure to copy your texture images into the right folder). Then refer to some of the example files to find out how to load them into your game.
basically, you dont need to do anything special with your models whilst building them in blender, just make sure you export properly. Currently there is no 'one-click' process to export an entire blender scene into ogre. If you want that, wait around for blender-ogre (which is some time off, but looks very promising).
Couple of tips: you will probably have to rotate your entities (in python-ogre) to get them facing the right way when exported from blender. Or alternatively, you could rotate them before exporting if they seem wrong in-game (remember CTRL-A -> apply size and rotation).
you must create a hierarchy in python-ogre to correctly create your game characters ie: mesh -> entity -> sceneNode. the sceneNode is the bit you'll usually be moving around with python. again check the examples or the wiki for this. its easy if you abstract some sort of loading routine, which will load any mesh and return a new sceneNode for it. the scene loader script can also take care of this for you.
also, beware of centering your models, ogre will completely disregard the model's origin point in blender, and just create the model from its geometric centre, so you will quite likely end up with models sunk into the floor. just adjust the entity position in python to fix this, then attach the adjusted entity to a sceneNode to move it around.
It probably will not work out first time, but stay with it. I have sucessfully exported tons of meshes into my pyogre game now, including animations, and it works fine with a little tweaking. The benefits over the blender game engine are too many to count here, but suffice to say, ogre is a lot more powerful than BGE.
hmm.. maybe that wasn't so brief. But you can't really illustrate the process with just a blend file and a python-ogre game, they are two quite different beasts!
A good practice i have found is to divide your project into 'source' and 'release' folders. put all your python scripts, dlls, configs and blender files in the source folder, and all your meshes / textures / sounds in the release folders. if you sort out your .cfg files properly (ie: use ..\release\models etc.), you will have no problems when compiling your project to exe.
hope thats of some help. Its easy when you have done it once. feel free to ask any questions, this is a nice friendly forum.