I'll do a comparison of the features of these 2 cameras and u can decide which is better.
Bracketing: Nikon D3000 No : Sony A330 Yes
Its a great function for beginners. Unlike pros who can determind exposure correctly most of the time (but not always, sometimes they use bracketing too), beginners are very poor in judging exposure. As such the exposure bracketing will be a godsend function when they are in doubt of the correct exposure. D3000 lacks this function. A330 has it.
Live View: Nikon D3000 No : Sony A330 Yes
Again, a great function for beginners. Pros who have used DSLR for donkey years will have no issue with using the OVF all the time. However for a newbie coming from a PnS, having a live view will be very good. Im not saying u have to use Live View all the time, but its good to use in alot of situations. And in certain positions, using live view will be more useful than using OVF. For example when taking Over the Head shots, there is absolutely no way u can use OVF. But u can still use the live view, especially since the A330 has a tiltable LCD screen.
Image Stabalisation: Nikon D3000 No : Sony A330 Yes
IS modes can reduce handshakes, compensating around 3 fstops of light. Thats good enough reason to have IS mode. The 3000D does not have IS build into their camera, thus you have to buy lenses which has IS build into it. But these lenses typically cost more than non IS lenses. The A330 comes with IS build into their camera, as such ALL lenses which they use becomes an IS lens. This is a major cost savings. Do you wanna pay extra money to buy IS for all your lenses?
In Body Auto Focus Motor: Nikon D3000 No : Sony A330 Yes
As the D3000 does not come with a build in AF motor, they can only use auto focus with AF-S and selected AF-I lenses. These lenses will thus cost more than similar lenses which do not require in lense AF motor. Besides cost, it also reduces the selection of lenses which the D3000 can use. Of cos you can still AF lenses which dont have in lense AF motor with your D3000, but they will only be usable in manual mode. If u buy an AF lens which cant AF with your camera, you are either insane, or u are too rich.
Wireless Flash Transmitter: Nikon D3000 No : Sony A330 Yes
Sony DSLRs comes with a build in wireless flash transmitter. The Nikon D3000 does not have this build in, so you have to buy a wireless transmitter which cost an additional few hundred dollars.
The Sony A330 comes with build in AF motor, so you can be sure they can work on all AF lenses. And do note that Sony alphas can use ALL Konica Minolta AF lenses. As such in terms of lens selection, the A330 actually has more lenses to choose from. Thus the lack of in body auto focus motor actually makes it cost more money in the long run, and also lessen the choice of AF lenses selection.
Price:
Nikon D3000 RRP $988
Sony A330 RRP $899
Sony A230 RRP $699
Im including the A230 here because it is identical to the A330, except it doesnt have Live View. So if you dont think you require live view, u can get the A230. Not only is it alot cheaper than the D3000, it has all the other benefits listed here.
So seeing all the facts above, its up to you to decide which camera is better.
PS: Adding Canon 1000D into the equation, i would choose the D3000 over the 1000D, due to 1000D's lack of spot metering mode, which I feel is pretty critical for me, but of cos this is subjective to different person's perspective. Some people probably wont ever use spot metering.