Apple’s (AAPL) business boom continues. The co’s Mac business, which covers several lines of personal computers designed, developed, and marketed by the Cupertino-based co. - is showing no sign of slowing down.

RBC analyst Mike Abramsky, according to Appleinsider - in a report to his firm’s clients, projects “massive back-to-school Mac sales” that could result in Apple shipping 3.04 million Macs. If projection proves accurate, this would represent a 44% year-over-year growth for the three month period ending September and a 22% quarter-over-quarter growth - up from his previous estimate of 2.8 million for Mac unit sales.

Abramsky’s study also revealed “unprecedented intentions” of part of the consumers, with “34% of respondents intending to purchase a Mac notebook in the next 90 days, while another 30% planed to buy a Mac desktop.”

The strong sales are directly attributed to two factors: the ‘Back to School’ promotion, as well as - what’s labeled as an “iPhone halo effect” where customers (17% of of consumers in the RBC study) have shown increased tendencies to purchase a Mac after first buying an iPhone.

Abramsky reiterated his expectation on Apple’s global market PC share to reach 4.2% in 2009, up from 2.9% in 2007.

Appleinsider also points out that “Abramsky has been one most accurate analysts covering Apple in recent quarters”.