Can I use my iphone 4 SIM card on an htc one x?

I have an IPhone 4 and recently received an Htc one x. Can I put my iphone 4 sim into the htc one x?

Yes as long as new phone is not locked to a differant network, if it is need to get it unlocked most cellphone shops can do it for around £10 or $15, just put it in and try it. If sim card is differant size might need a sim card adapter too around £5 $10

Yes, You can do it.
Before put your sim card on your HTC One X phone, Make sure your phone is unlocked. If it's locked means, you will need to unlock your mobile. For unlocking you can approach your service provider or else try to buy an unlocking service from any one of the online unlocking service provider like http://www.unlock-zone.com/htc-one-x/rs5wp9/ Here you can remove your network lock at low cost and you can get free unlock instructions from http://www.mobileunlockguide.com/htc-one-x I hope it will be very useful to you.