You can't work without the proper authorization but you can certainly fly over to the US to attend a job interview. I did that myself and was honest when going through US Immigration. When they asked the purpose of my visit, I told them I was attending a job interview. I showed them the letter inviting me for interview. Then I was asked to show my return plane ticket. Once they saw that, there was no problem. I got the job and returned to the UK to start the H1-B visa process. Always be honest with US Immigration - being caught out on a lie will cause you much bigger problems.