Robert Parker is a 24 year old ex-web developer living in New York city. In the wake of the conversion movement, he has seemingly lost everything. Haunted by the same nightmare every night, he soon realizes that he must make a choice.

To those unfamiliar with the Conversion Bureau: it is a scenario created by an author named blaze in which Ponies either appear in the human world or have lived beside humans without incident for millennia. One day, in the face of all the damage humanity has done to its world, the ponies offer a solution: undergo conversion to become a pony and allow the world to be inundated with Equestria's influence: thus healing it and bring forth a golden age.

Many different authors have taken many different approaches to this idea, all of them are worth checking out.

http://www.ponychan.net/chan/fic/res/53616.html (The current thread)
http://www.equestriadaily.com/2011/04/conversion-bureau-compilation.html (The compilation post on EQDaily. *NOT UPDATED*)

Mailponies, the couriers of Equestria, carry important documents and packages back and forth throughout the land. Known for being kind, steadfast, and reliable, they are bound by a code of conduct detailing how to behave. In this code, an emphasis is placed on camaraderie between fellow mailponies. They are to trust, assist, and cooperate with each other whenever they can.

When mailmare Ditzy Doo finds an injured stallion by the edge of the Everfree Forest, she takes him under her wing. Upon waking, she discovers that he is, in fact, another mailpony, bound by the same creed as her. Through an adherence to the rules and the kindness of her heart, she allows the stallion to stay with her until he recovers. What will life be like for him under the Doo roof? More importantly, will he survive Dinky?

Art by http://artistic-derp.deviantart.com/

This story is a sequel to An Azure Future

Not too long after being ponified, John must find a mate in order to maintain his pardon. So nine years after his wife left him, he must venture out into the dating scene.

Unfortunately, he has to deal with Field Trips, HLF remnants, crazy ex-PER members, even crazier mares and the horrors of a social life. No one said moving on would be easy.

Highly recommended to read An Azure Future prior to this.

WARNING: EXCEEDS RECOMMENDED DAILY DOSE OF WING BONERS.

John Norris is another broken man in the last days of humanity. It has been years since he last left his apartment for something outside of restocking his food and water supply. Enter Azure Wind, a young pegasus colt, bearing a letter that explains he is his son. The two bond and much is learned by both in this light hearted comedic tale.

A conversion bureau fic.

Now with 27.6% More Sequel!

Find it Here!

It's almost Mother's Day. Scootaloo comes to Rainbow Dash with a startling question, but then backs off, feeling ashamed she asked it. Rainbow Dash, taken off-guard by the question, starts to question both herself, how she feels about Scootaloo, and about her past...

Dinky enjoys staying with Sparkler, but is still anxious to go back home to her mom. The bright young filly and the young-at-heart mare use their time together to teach each other about growing up and what it means to be family.
A sequel to Ditzy Doo's Dismally Derpy Day.