You will probably get as many different responses as responders to this question!
There are many approaches to fertilizing an orchid. Foremost, you should know they are very light feeders compared to most other plants we grow. In nature, many orchids are epiphytes, their roots are exposed and are only fed by runoff from rain. You should mimic this in your home culture by cutting the fertilizer dosage of anything you get by at least half.
Next, you should look for fertilizer with nitrogen that is at least in part derived from a non urea source. Urea relies on bacteria to break it down into a usable source for plants. As orchids are generally potted in bark, there will be few to no beneficial bacteria to do this for you.
Aside from that, just about any fertilizer will do. I use organic fertilizers myself, but this is totally up to you.
Hope this helps.

It depends on the type of orchid. ie. a phal = light feeder, vanda = heavy feeder. Fertilizing is not as big of deal(in general) as with other types of plants. And, in general, orchid don't "need" fert while in bloom.
Again, more info on type of plant will yeild a more detailed and useful answer.

Thanks to both of you for replying. The orchid is a phal and is in a spot that gets filtered light all day. It seems very happy at this point. Any other suggestions would be great.

When you plant comes out of bloom your fert should be weakly/weekly. I also use Age Old Organics, but you can use anything...Just dilute it if the numbers are high. Too much fert will burn the plant.

And you are a good kid for getting your mom an orchid!

Thanks for the clarification. I think my mother is hooked; she loves that orchid!

there are a variety of companies that sell "orchid food" like Miracle Grow and such. They are water-soluable granules when mixed at a teaspoon per gallon of water. Some people add a few drops of SuperThrive. I actually feed my cattleyas diluted fish emulsion. But it has a bad smell.