Need advice on locked phone options

[familyguy]

Cut a long story short I was made redundant recently and the company subsequently closed.
I was given a phone a blackberry curve which I never ended up using.
Basically I've been left with it and I have an iPhone anyway so have no use for it.
When I switch it on an O2 screen comes up and the phone has an O2 badge below the space bar.

I put in my old tesco sim card and I can access the menus and so on but it says invalid sim card at the top of the screen.

So in order to either use or sell this phone for someone else to use do I need to bring it to O2 to unlock or would I be better off going to one of the small unlocking shops?

I don't really know much about them hence my thread.

Thanks

 

[familyguy]

You could do either, it would probably be cheaper if O2 would give you the unlock code, go in and tell them you are going abroad to another EU country for a couple of months and they just might give it to you.

Thanks.

 

[chrisboy]

Just fill this out. Save having to go to the shop..

[broken link removed]