Consider the following:

-I am a U.S citizen, 28 years old
-I'm going to study abroad with my school, California State University, Fresno. The program last for 2 weeks, starting near the end of June this year.
-After the program, I want to continue my stay. My plan is to telecommute via the Internet and continue work with my current employer (Pelco, a U.S-based company, that was recently acquired by Schneider Electric, a French company) to support myself for up to another 2 months. The Pelco office where I work is based in the U.S. in Clovis, CA.

Pelco has a sales office in Australia at:
Pelco
12/2 Pyrmont Bridge Rd
Pyrmont NSW 2009, Australia
(02) 8572 5700


1. Which visa would I need to accomplish this (or is it even possible)? I took the online wizard and it suggested:

-Work and Holiday (subclass 462) visa
-Higher Education Sector (subclass 573) visa

I'm not sure which one, or if my circumstances would require a different one.

2. Will I need any special work permit? Since Pelco is based in the U.S., I'm not actually "working" in Australia; I would just be using the Pelco sales office as a facility to access my Pelco intranet and VPN in back home. Or is my logic flawed here?

Thanks!

A two week study is not like a structured course for which a student visa is for and in fact you need approved study courses to get one.

You are allowed to do short term study [ up to three months specified for the 676 tourist visa ] on tourist visas and the ETA 976 is the cheapest [ it also mentioning short study though not specific but same rules as for 676 would apply ] Visa Options - Tourists - Visitors - Visas & Immigration

I'd save your 462 just in case you get such a liking for the place and want to return [ need to apply before you turn 31 ].

The tourist visas do not allow working other than with something like WWOOF Australia where it's not for money.
But what you propose to do is not really working either in that you are not getting employed here nor being paid, what one could just describe as maintaining a connection with your employment abroad while on holiday.

So the ETA ought to be fine.
If you bring a laptop or any other work related stuff and get quizzed by immigration, you just indicate you're here for the short course and will be keeping in touch with your employer whilst abroad.

You could also get the ETA - business variety and then you would be even better covered.

If you're planning on wanting to get out of Sydney a bit, have a look in our travel section re links for flights etc., even some cheap overland travel available by doing campervan relocations - http://www.standbyrelocs.com/
http://www.travelmate.com.au/Home/Home.asp , a good travel planner.

Is it necessary for the employing US-based company to have a branch in Australia for this to succeed? What happens at the end of the ETA period? How can one extend it for say, roughly four years?

What BillyB is proposing to Brent is probably a bit different to you and certainly nothing like staying for four years.

If that is your intent, you'll need to get a visa that allows that, either employer sponsor [ and that can be via a company based overseas ] or an independent skilled visa.

Okay, thanks, Wanderer. I'm guessing the employer sponsor path would affix me to my present employer and that if anything rifted between us, I'd have to reroute and complete a different visa to stay in Tassie.

That said, i'm eying the independent skilled visa with which I could decide to continue employment with my present employer, correct?

Lastly, I'm scheduled to return for training in May and then again in September. I think I'm in a bit of a pickle in that it's already March. Would staying on a three-month tourist visa from May through July affect getting a second tourist visa to return for the class again in September?

Just a note that the training is not something that directly affects my job. It's very much a personal choice which I look forward to contining.

So I take it the training is that you're attending courses rather than being employed as a trainer.

If that's right, you could get separate tourist visas but you also do what you're intending to do on an ETA - link in response to BillyB.