Not everybody's down with free file-syncing service Dropbox, but that's not a problem with free web app AirDropper. Use it to request a file through email or password-protected link, and when they upload it, it goes right into your Dropbox space.
AirDropper authenticates itself with your Dropbox account, then asks you to fill out a request form for the file you're looking to receive. After providing the email address of the file-haver or getting them a password-protected link through other means, they'll get to a page that simply asks them to browse and select the file, then upload it. That file lands right in your Dropbox account in a folder you specify, and the world feels ever more connected.
It's a nice go-between agent for clients who can't send a large file out via email, or for pinging you friends and reminding them to send along that MP3 you were talking about last night.
AirDropper is free to use while in beta but will eventually take on a "freemium" tiered pricing model that keeps a free option, according to its developer. It requires a free Dropbox account and an authentication if your browser cookies get wiped.