Sometimes you acquire house plants as gifts, clippings or maybe an inheritance, and you end up not knowing anything about the plant except that it looks good. Identifying house plants by photo can take some time, but it can usually be done with some research and exploration of a few different avenues.
Take note of your plant's different features, for example number of leaves, leaf shape, type of stalk or stem and colour. It is best to try to identify house plants when they are healthy and mature. Immature plants or unhealthy ones may not resemble pictures of healthy plants.
Use online resources. Texas A & M University has a website pictures and good descriptions of house plants. Find the plant that looks most like yours and go from there. Another good online resource is gflora.com, but you need to click on the names of the plants to be able to look at the photos. It may seem like a roundabout way to go through the process, if you have no idea of the name, but that is how it is set up and the descriptions are useful.
Ask for help online by using Gardweb.com or UBCbotanicalgarden.org. Both have popular message boards especially for plant identification. All you need to do is post, asking for help and upload a photo of your plant, and others can help with the identification.
Visit the local library and leaf through the many books they have on the subject of house plants. Many books have more photos than you can find on the web and may be more helpful. Lowe's and Home Depot sell inexpensive guides to house plants with lots of photos.
Spend a couple of hours visiting nurseries and garden centres with a picture of your plant and see if you can find the species. Ask the staff if they can identify your house plant.