Hi again

No, it won't matter how long you have been married, you will just need your marriage certificate.

We have never been to Australia before either and there are many others on here in the same situation, go for it!!!

The sponsored visa (I believe) is usually alot quicker and there are job sites where you can post the CV of the second applicant if they are not being sponsored, which should result in some interviews when you get out there.
Try seek.com.au linkme.com.au hays.com.au jobs.ozfreeonline.com.au
these might give you some more idea on the jobs front.

Hope this helps

Julie