Is this my name in Japanese?

[Tomii515]

Thomas (Tommy) Ryan Kurpit.

Tomasu (Tomii) Raian Kuurupiite.

I'm not sur eof my last name XD

[doinkies]

Well, the first and middle names seem to be OK, but doinkies would spell the last name as "Kurupitto".

Your name as written in katakana would be トーマス・ライアン・クルピット, then.

[KrazyKat]

In katakana we write トミー not トミイ for tomii (from your signature)

[MorganaBloodthirst]

how is Catherine or Katherine in japanese?

[KrazyKat]

http://www.japanesetranslator.co.uk/your-name-in-japanese/
http://www.japanese-name-translation.com/site/japanese_names.html

[kevinsano]

キャサリン
kyasarin

[Da Monstar]

my last name is Pitason?!?! I am no Son of a Pita!

[doinkies]

Well actually, in your case, the vowels i and a would be lengthened, so your last name written in Japanese would actually be ピーターソン (Piitaason).

Then again, that would be with the English pronunciation of Peter...I don't know how it's pronounced in Danish.

[Da Monstar]

danished pronounciating of peter is not with sqeeky e as in english.. both e's is pronounced as the last e is pronounced in english

[doinkies]

Ah, so it's pronounced "eh" and not "ee"? Well in that case, it would probably be ぺテルソン (Peteruson), then.