hi imageworks,
My wife was in a similar position last year. She was told to fill out the Tr1 form to register as self employed. Then in the following October (2011 for you), Revenue told her to fill out a Form 12 for the previous tax year (given the three different sources of income) to file her tax return indicating her income from both self employed work and job seekers benefit during that year.
Also, so long as you are not working self employed for more than three days a week you'll you'll be able to claim job seekers benefit for the three or more days a week that you are not working (remember its a 6 day working week for JSB).
Remember, your tax return is a year away but you should try and hold back a few quid for tax so you don't get a shock at the end. In your tax return you can write off lots of stuff to lower your taxable income. keep receipts for everything.
You should pop down to the citizens information centre, they usually have a monthly free advice evening from professionals like solicitors and accountants - you need an accountant to give you a little steer but its very doable.
good luck.