SSH for iPhone and iPod Touch
[This is a peculiar development platform in that Apple, Inc. insists on having absolute control over all iPhones, i.e., being the sole conduit for acquiring and installing applications. (Determined purchasers can temporarily "jailbreak" the device, but run risks by so doing.) Accordingly, uniquely for this DRM-imprisoned platform, primary hyperlinks will (except for Dropbear) almost certainly be those at the Apple iTunes Store (which are not real hyperlinks, but rather redirects that attempt to launch the iTunes application and require you to consent to the iTunes Store's licence agreement to get further information), but I'll try to also include developer links.
Also, all of these applications (except Dropbear) so far are available solely through the iTunes Store.
Last, Apple, Inc. also require in the iPhone Developer Program License Agreement, section 5, that developers' licensing "not purport to require Apple (or its agents) to disclose or make available any of the keys, authorization codes, methods, procedures, data or other information related to the Security Solution, digital signing or digital rights management mechanisms utilized as part of the Program". Consequently, there cannot be applications for iPhones (except rare jailbroken ones) under open source licensing: All iPhone apps are required to be proprietary.]
Dropbear by Matt Johnston, ported by anonymous coder "Nightwatch", can be installed after jailbreaking your iPhone. Source & binaries under an MIT/X11 licence. Supports X11 forwarding, and authentication-agent forwardingfor OpenSSH clients. Includes scp and other traditional SSH functions. ssh protocol v. 2.0.
[Gone from http://www.abigato.com/iphone-ssh-kit-vr1.tar.bz2 ]
iSSH by Dean Beeler ("Zingersoft") is a PuTTY port to iPhone and iPod Touch, supporting SSH client terminal access with VT100, VT102, VT220, ANSI, xterm, and xterm-color terminal types. Supports password authentication only in v. 1.0; will add RSA public-key support and generation in v. 1.1, along with X11 graphical support, non-standard ports, and other features. Unlike pTerm and TouchTerm, this application is available to iTunes Store customers browsing from IP addresses outside the USA and Canada. Protocol v. 2.0 & 1.5. Client only. Proprietary.
pTerm by Eric Maland ("Instant Cocoa") is a PuTTY port to iPhone and iPod Touch for SSH and telnet vt100 or xterm terminal access. Supports public key (RSA/DSA) and password authentication. (However, there is currently no way to transport public keypairs to our from iPhones or iPod Touches.) Supports key generation. Downloadable by US and Canadian iTunes Store customers only, on account of US crypto export restrictions. Protocol v. 2.0 & 1.5. Client only. Proprietary.
TouchTerm by Jim Brink ("brink.net") is an OpenSSH/OpenSSL port to iPhone and iPod Touch for SSH and telnet vt100 terminal access. Does password authentication and RSA/DSA public key authentication. Downloadable by US and Canadian iTunes Store customers only, on account of US crypto export restrictions. Protocol v. 2.0 & 1.5. Client only. Proprietary.
TouchTerm Pro by Jim Brink ("brink.net") is an OpenSSH/OpenSSL port to iPhone and iPod Touch for SSH and telnet vt100 terminal access. Can do either password or RSA/DSA public key authentication, can create and use stored connection configuration and use sundry add-ons. Downloadable by US and Canadian iTunes Store customers only, on account of US crypto export restrictions. Protocol v. 2.0 & 1.5. Client only. Proprietary.