well, ive been a long time lurker so i though its about time i posted something.
Ive recently started my third Planescape Campaign, my first since the faction war. Its got a pretty 'epic' storyline at the moment - with the campaign focussing on an offshoot cult of Orcus that is trying to get Tenebrous resurrected (using Tome of Magic and the Binder rules quite a bit for this). well, to cut a long story short, i've placed Tenebrous in a planar rift between the astral and Orthrys in Carceri and the adventure is to culminate with a ritual of possession in which the chief villan will use her own bodyas a vessel for the newly awakened Tenebrous to inhabit and rise as a new god...
well, my proplem is i know very little about Orthrys (only what is puplished in the AD&D manual of the planes and the 3e manual of the planes. I was never able to purchace planes of conflict and was wondering if anyone oculd fill me in on the dark of this swampy layer...
thanks for your time
New Campaign!
I'm sure that's not correct. Otherwise, PW would be very kind and host all the Planescape books for us.
that does sound a bit too good to be true, but ill see what i can find anyway... 
A search on a site such as RPGNow.com shows the PDFs that they have of Planescape products for sale: http://www.rpgnow.com/search.php?query=planescape&sortby=p.products_name.
There are other sites that also offer the PDFs for sale. I'm not sure what the quality is of the products or which site is the best to buy from in terms of price, customer service etc.
I have always had good luck with RPGNow. I purchased a good number of my Planescape books from them - in pdf. format - and have no particular complaints. The downloads tend to be quick and the sight keeps a record of your account so you can download those again should you loose them at no additional cost. (you simply resend the download link to your e-mail address by a convenient button on your purchase history page)
My only complaint, is that occasionally the search results aren't complete. For example, if you do a search for Planescape, you may not come back with all the results you would if you searched for a particular book and then followed the exact link from its header. (for example, looking up Planescape will produce a much smaller list than AD&D Planescape, which one might not know unless they had linked to one of the order pages and then backtracked by hitting the "AD&D Planescape" portion of the site address key at the top of the page.)
In fact, for your convenience, here the best link: (more complete than that offered above - no offense to the poster there)
http://www.rpgnow.com/default.php?cPath=297_310&
adnd stuff isn't liscenced anymore so if you can find it for free ya can DL it. in fact every now and then WoTC offers some stuff off their site. for the other stuff there is an online store with everything, they charge $5 per DL I think. not sure on the link...it should be on the WoTC site