Network operator O2 will be feeling mildly pissed off today, because rival operator Orange has officially welcomed the iPhone onto its network.

The hued operator announced in late September that it would “bring the iPhone 3G and 3GS to Orange UK customers later this year”, and today’s the day.

Buyers can pick-up the iPhone 3GS in either black or white and with a 16GB or 32GB storage capacity. The old-school iPhone 3G is only available in black and with an 8GB capacity.

Various monthly tariff options are available and prices vary according to which non-O2 iPhone model you want. Opt for the killer 32GB iPhone 3GS and £30 ($50/€33) per month tariff, for example, and you’ll have to fork out £274 ($457/€304) for the handset.

Shell out £73 ($121/€81) per month and you’ll get the phone for free, though.

Pay-as-you-go plans are also available, Orange said, but you’ll have to pay a credit card crumbling £539 ($900/€600) for the 32GB iPhone 3GS. The iPhone 3G is a more palatable £343 ($572/€381) on Orange PAYG.

Further information about Orange’s various iPhone price plans is available report now. ®