There are ways of doing it natively using emails; but there is also a Juiced Technologies' tool to do this as well if you want something more sophisticated.
Sending sms notifications via email involves knowing the correct format for each phone providers network to send sms throught email.
Case([Cell Provider],
"AT&T",[Cell # (as number)]&"@txt.att.net",
"Verizon",[Cell # (as number)]&"@vtext.com",
"T-Mobile",[Cell # (as number)]&"@tmomail.net",
"Sprint PCS",[Cell # (as number)]&"@messaging.sprintpcs.com",
"Virgin Mobile",[Cell # (as number)]&"@vmobl.com",
"US Cellular",[Cell # (as number)]&"@email.uscc.net",
"Nextel",[Cell # (as number)]&"@messaging.nextel.com",
"Boost",[Cell # (as number)]&"@myboostmobile.com",
"Alltel",[Cell # (as number)]&"@message.alltel.com",
"MetroPCS",[Cell # (as number)]&"@mymetropcs.com"
)
I have this working in one client's app.