File transfer over the air with iPad

I have an iPad app that outputs a PDF file that needs to be uploaded to a remote server. What are my options here? Is there a sFTP or FTP implementation 开发者_JS百科for iOS that would help me achieve this? Can it be done using other protocol?

Thanks!

FTP Client Wrapper in Objective-C for iPhone

ConnectionKit (might not be iOS compatible)

How about HTTP? http://www.cocoadev.com/index.pl?HTTPFileUpload

EDIT: SCP using libssh2? http://www.libssh2.org/examples/scp_write.html

This on costs money: http://www.chilkatsoft.com/ssh-sftp-objc.asp

Haven't tried it myself yet.

(And a duplicate on SO: Upload file from iphone using SFTP protocol)