Easy. Get a 1x6, carpet it. Secure it from the ledge to the floor, making a
ramp. Cats *love* ramps.

Sherry

Are you handy? Can you build a ramp from the window down to the floor beside
the bed? That would give them access down not directly on you. I'd also
honestly think about moving the bed, myself. SOunds like a perfect set up
for a little kitty ramp and rest stop to me though.

I had a similar situation when I visited my sister.  In my case, my cat
would use the edge of the bed to jump to a window ledge where we had
attached a seat, then would also jump from the window to the bed.  I did
have fears that she might inadvertently scratch my eyes in one of those
leaps --  so, I put my pillow at the foot of the bed and slept with my feet
to the wall when I was visiting.  That protected my eyes, I wasn't concerned
about whether Holly might land on my feet (covered with blankets), and I
slept just as well using that "reverse" arrangement.  You might also
consider moving the ledge to another area of the room.  Of course, the best
idea is the ramp that Sherry and Karen suggested, but I added my suggestions
in case that won't work for you.

MaryL

If you don't have enough room for a ramp, you can use staggered wall shelves
as steps or vertical wall shelves with staggered climb-through holes.
Bookshelf kits can also be adapted for vertical climbing without damaging
the wall.  Floor to ceiling scratching poles with perches are another
alternative.

http://maxshouse.com/Environmental_Enrichment/high-level_walkways.htm

Play it safe and compromise:  move the bed.

--
Barb
Of course I don't look busy,
I did it right the first time.

thanks for all the suggestions.  They are all cat-friendly suggestions
tho.  I'd rather deny them access to the window ledge entirely if
possible, rather than building a ramp or steps.

<delurk>

I have no personal experience with the following suggestions, so take 'em
as you will.

I have read that some cats don't like the smell of citrus.  Perhaps you
could cut up some orange peels and put them on the ledge, or maybe just
spray some citrus scent on it.

I have read that some cats don't like to walk on aluminum foil.  I don't
know if the foil is supposed to be crinkled up or not.  Perhaps you could
try lining the surface of the ledge with aluminum foil.

</delurk

An option you might want to consider to dissuade your cats from getting on the
ledge is "sticky"  tape placed with the sticky side up.  I've successfully used
tape (the kind used for sealing packages)  to keep my cats from areas where
they are not welcomed -- the dining room table and kitchen counters, primarily.

Gayle

I know I say this a lot but, double sided tape has a LOT of uses. Maybe a
little strip of it along where they jump up ?  They won't like to be stuck
to the tape and will cease and desist... well hopefully.