Also, you can look here for pets being rehomed by their owner:

Petfinder Adoptable Pets-Scroll down and click on "adoptable pets".

Listing arranged alphabetically by City:

Animal Defense League of Washington County Inc.-Abington (PetFinder Link)
Assisi's Animal Rescue Group-Annandale (PetFinder Link)
Animal Welfare Action Group-Appomattox
Capital Animal Care-Arlington (PetFinder Link)
Homeward Trails-Arlington (PetFinder Link)
SPCA of Northern Virginia-Arlington
Hanover Humane Society-Ashland

Barkshire Woods-Bealeton
Bedford Humane Society-Bedford (PetFinder Link)
The Animal Welfare Foster Program-Blacksburg
Animal Hope Alliance-Blacksburg (Petfinder
Critter Care-Blackstone (Petfinder Link)
Planned Pethood Clinic/Franklin County Humane Society Inc.-Boones Mill (PetFinder Link)
Holly Help Memorial Spay-Bristol (PetFinder Link)

Lost Fantasy Stables and Animal Rescue-Ceres (PetFinder Link)
Lost Dog and Cat Rescue-Chantilly
A Forever-Home Rescue Foundation-Chantilly
Spay/Neuter All Pets Society-Chase City (PetFinder Link)
Saving Animals From Euthanasia-Chester (PetFinder Link)
Homeless Animal Protection-Placement-Education-Chesterfield
VA Partnership for Animal Welfare Support-Christiansburg (PetFinder Link)
Humane Society of Montgomery County -Christiansburg (PetFinder Link)
Friends of Animal Care and Control-Christiansburg
Lake Country SPCA-Clarksville (PetFinder Link)
PAWS of Southwest Virginia, Inc.-Coeburn (PetFinder Link)

Janet's Rescues and Placements-Dale City (PetFinder Link)
Noah's Ark Foundation-Dale City
The Pulaski County Humane Society-Dublin
Save a Dog, Save a Cat-Dumfries

PerPETual Care-Edinburg (PetFinder Link)
Emporia Greensville Humane Society Inc-Emporia (PetFinder Link)

H.A.R.T-Fairfax Station
The Pet Haven-Falls Mills
Partners Among Cats & Canines-Franklin
Rappahannock Humane Society Inc-Fredericksburg (PetFinder Link)
SPCA of Fredericksburg-Fredericksburg
SPCA of Fredericksburg-Fredericksburg (PetFinder Link)
Whiskers-N-Wags-Fredericksburg

SOS-Pen Pals -Glen Allen (PetFinder Link)

Pet Rescue Foundation, Inc.-Hadensville (PetFinder Link)
Twin County Humane Society-Hillsville (PetFinder Link)
Furry Suits Rescue-Herndon

King George Animal Rescue League-King George

Humane Society of Loudoun County-Leesburg
The National Humane Education Society-Leesburg
Louisa Humane Society-Louisa
Almost Home Pet Adoption Center-Humane Society/SPCA of Nelson County Va.-Lovingston

Madison-Greene Humane Society-Madison
For The Love Of Animals In Goochland-Manakin-Sabot
SomeBuddies Inc. -Mechanicsville (PetFinder Link)
Friends of Homeless Animals-Merrifield
Middleburg Humane Foundation-Middleburg
Deer Run Animal Wellness Center-Midlothian (PetFinder Link)
Northern Neck Humane Society-Montross (PetFinder Link)

Boulevard Veterinary Hospital-Newport News (PetFinder Link)
New River Valley Animal Shelters Online-New River Valley
Rainbow Animal Rescue-Newport News (PetFinder Link)
Animal Rescue Of Tidewater-Norfolk
Rainbow Animal Rescue Inc.-Norfolk
The Norfolk SPCA-Norfolk
P.A.W.S. of Southwest Virginia, Inc.-Norton
Loudoun SPCA-Northern Virginia

Rikki's Refuge-Orange
Orange County Humane Society-Orange

Caring For Creatures-Palmyra
Lee Animal League-Pennington Gap (PetFinder Link)
Blue Ridge Veterinary Associates-Purcellville (PetFinder Link)
Second Chance Animal Shelter-Powhatan
New Journey Animal Rescue-Powhatan (PetFinder Link)

Animal Life R.A.F.T.,Ltd.,New Kent, VA-Quinton (PetFinder Link)

Pound Pals of Radford/Radford Animal Shelter-Radford (PetFinder Link)
Pound Pals of Radford-Radford
Radford Humane Society-Radford
Paws and Claws Animal Rescue and Humane Education Society-Reston
Save Our Shelters-Richmond
Save Our Shelters-Richmond (PetFinder Link)
Richmond SPCA-Richmond
Richmond Animal League-Richmond
Henrico Humane Society-Richmond
Shelter Adoption & Rescue Efforts (SHARE)-Richmond (PetFinder Link)
Cat/Canine Adoption and Rescue Efforts (CARE)-Rustburg (PetFinder Link)
Animal Welfare And Rescue Efforts Inc.-Rustburg (PetFinder Link)

Halifax County Humane Society-South Boston
Pet Assistance League of Virginia-Stafford (PetFinder Link)
PAWS and WHISKERS Animal Rescue, Inc. -Stephens City (PetFinder Link)
Patrick Animal Welfare Society-Stuart (PetFinder Link)
Animals In Need-Stuart (PetFinder Link)
Spay/Neuter Inc.-Stuarts Draft (PetFinder Link)
VA Orphan Rescue-Suffolk (PetFinder Link)
PAWS for a Cause, Inc. -Suffolk
Surry County SPCA-Surry (PetFinder Link)

Animal Connections-Troy

The Virginia Federation of Humane Society-Virginia State
Tidewater Humane Inc.-Virginia Beach
Hope for Life Rescue-Virginia Beach
Diamonds in the Ruff Pet Rescue-Virginia Beach
Web of Life Animal Outreach-Virginia Beach (PetFinder Link)
Pet Guardian-Virginia Beach (PetFinder Link)

Animal Resource Foundation-Yorktown (PetFinder Link)