Sim card help for Iphone 4 please?

I'm currently using a samsung galaxy Y phone which I really do not like and want to get an Iphone4 but I know this uses a micro sim card and I have an ordinary one.
My question is can I cut it down to fit the iphone or do I need a new one.
Thanks
And if anyone has any advice on the best phone to get I would be very grateful as My galaxy Y has virtually no memory in it and its driving me mad

Some phone shops do have the tool to actually cut the sim card down to a micro sim. How ever you may be able to phone your network provider up to actually transfer your sim details over to a micro sim.

So, you want to swap a phone that is expandable up to 32Gb for a phone that isn't?

Memory Card slot microSD, up to 32 GB
Internal 180 MB, 290 MB RAM

Also you want to swap to a phone that doesn't store information on the sim?

Why would you want to do either of those things?

You have 2 choices

1 - just ask your network to send a replacement Micro SIM
(or ask in the sho)
This is by far the best way!
(you could even sign up for a free PAYG SIM, and then ask to SIM Swap them,
or just ring them up and say it is not working reliably, and they will send you a replacement - you just tell them the new size - O2 and some networks send a dual size one anyway)

2 - Get a phone store to cut it down with a punch tool.
BUT… The edges of the cut down one are often too sharp and can stick in the slot of the phone - so beware.