No problem.
The reason for this is that iOS is locked down tight. It has taken months to come up with a jailbreak and this gives an indication of how difficult it would be to write and propagate a virus.
Also, any virus protection would have to hook into the OS, and Apple will simply not allow this.
Same goes for malware/spyware. It can't hook into Safari, so it can't hijack your browsing.
IF, and this is a very big if, there are ever any viruses written for iOS you WILL be able to read about it here. I guarantee we will be all over it.