The question regarding email and e-mail is not yet settled.  The American Heritage Dictionary (4th ed., 2000) comments that "email has recently been gaining ground over the forms E-mail and e-mail, especially in texts that are more technologically oriented."  However, the hyphenated form of e-mail is still widely used, and it may prevail as the "e-" (for "electronic") prefix is attached to other words.  In this writer's opinion, we will not adopt such one-word usage as ecommerce, ebusiness, and etrade.  Since these words and others like them are most likely to use a hyphen (e-commerce is currently the only accepted usage in the AHD), we may expect e-mail to follow the same pattern.  However, if it does not, it will not be the first time that English language and orthography have taken an inconsistent and divergent path.