Preserving pears

Do you mean bottling pears? If so, I often do this. This link will give you more specific info as well as more bottling articles listed at the bottom:
http://www.allotment-garden.org/allotment_foods/bottling-canning/Bottling-Canning-Methods.php

Basically, I prep all my bottles first and have the water bath and simple syrup ready. Then I take almost ripe pears and peel, quarter, core and slice them into a big bowl. I do only a few jars worth at a time so the fruit won't go dark. Fill the jars with fruit but only to within an inch of the top. Pour in hot syrup into each jar, poke a dull knife around sides to loosen air bubbles, top up syrup where necessary. Wipe jar tops off, place lids and rings on, and when I have enough jars to fill a boiling water bath pot, I put them to boil for 15 -20 min. Notice, the water bath is already boiling when the jars go in. I always set a timer. Once done, Remove carefully and let cool out of the way. Then check seals.

Another thing I do with ripe pears is to make pear juice/nectar. I wash down overripe pears, remove stems, bad spots, quarter them and add to a heavy bottomed stock pot with just a bit of water in the bottom to prevent scorching. I then set the pot on low and let it cook for an hour or two. Slowly is the key. Once mushy, I run the lot through a special strainer like a passata machine. I return it to the heat, sweeten to taste, then bottle them and waterbath them for about 15 minutes. If you don't want to invest in a strainer machine, then simply peel, core, and de-stem the pears before putting into the pot for cooking to mush. You can adjust thickness with a bit of water if necessary.

Here are some more ideas:
http://www.allotment-garden.org/recipe/category/fruit-recipe/pears-recipe/

There are a few more recipes here

http://www.allotment-garden.org/recipe/category/fruit-recipe/pears-recipe/

I can thoroughly recommend the pickled pears -- I make these to accompany our Christmas lunch every year