Sim card Czech

I've always used Vodafone and been quite happy with them. A new Sim card is 500Kc and with that you get 500Kc worth of call credits. O2 is another company and I'd imagine they would have a similar offer.
It works out a lot cheaper to call or text other customer s of the same company, so if there are certain friends or colleagues you'll be calling frequently it might pay to find out which phone company they use.

Are there just the global providers, or are there local ones too, these seem to be cheaper in most countries.

Cheers,
Helen.

There are three country wide companies which have basicly similar coverage, you can compare prices of prepaid service:
http://eshop.vodafone.cz/tariff.htm?lang=en&ttype=1
http://t-mobile.cz/Web/English/ServicesAndTariffs/Twist-PrepaidService.aspx
http://www.cz.o2.com/osobni/en/tarify_a_volani/tarify/mobilni_tarify/index.html
All of them are global in meanings of the owner.

They offer standard post paid services, of course.

There is a fourth one which has much smaller coverage: http://www.ufon.cz/en/c/coverage-map/cr.htm, but it might fits your needs. Unfortunatelly I don't know any experience with ufon.

Jirka Nouza

I pay just 2 crowns for SMSs worldwide with my t-mobile, pay as you go, with the 'text appeal' option. This applies for SMSs sent from within the Czech Republic.