I've been fired - what do I do?

All,

Require some help/suggestions on my next course of action.

As the topic header indicates, I've been fired from my current firm - I was an Analyst, with around 8 months of experience.

My background: I went to Reading University in the UK (I'm UK based), had a decent B grade marksheet and did internship at ABN in the operations office.

However, when it came to the recruiting phase in November 2004, I knew that my current background wouldn't help me as much, especially when I saw the competition. Therefore, I did the STUPIDEST thing I could have done - alter my grades, to A, and upgrade my internship to a front-office role.

I winged my way through interviews and was lucky to have been offered a place at a top-5 M&A house (globally). I couldn't believe my luck! They only did random spot checks, nothing in detail, for which I was initially relieved.

I promptly started in September, went to NY for training, came back, posted to the FIG team. All went swimmingly, my boss liked me, as did the team. Got to do financial modelling / pitchbooks, all the usual lark.

Got an email from HR around a month back - they've spotted irregularities, could I come in for a discussion? I went in - present were all the top HR personnel, my line manager (with a disgusted look on his face) and the head of i-banking. The HR lady told me that my grades / internship specification doesn't match what I wrote, I tried to bullshit at first 'I don't know what you're talking about' etc... but it wasn't going anywhere.

She said that this was a serious disciplinary event and that I was going to be fired. Needless to say, I was devastated. My boss told me that I made a fool out of him, I did NOTHING of the sort - he said not to count on him for any references.

How do I explain this to future employers? Will I even get interviews? Please be serious - I am totally unsure as to what to do.

Thanks.