My preferred order of being contacted is as follows:

• Instant Messenger (Skype or Gmail)
• Twitter DM
• Email – tim.reader@gmail.com
• SMS — 07808 205178
• Phone (often goes to voicemail – will reply asap) — 07808 205178

Skype name: timboreader

Twitter: twitter.com/timboreader

If this all sounds a bit prescriptive, check out Tantek Celik’s Communication Protocols!