any luck with straight talk wireless?

just got an iphone 4 from my friend under settings there isn't a carrier listed, I know it's a gsm phone. So I went to wal mart and purchased straight talk wireless activation kit. I put in correct sim card the phone says its" searching" then it simply says no service. I called the number I was given on activation instruction, the short version of what i was told is that I needed to wait an hour . Been almost hour now and still nothing. Hoping someone has had similar experience and worked it out. Please let me know and thank you in advance. Also I removed rear cover to make sure antennae was plugged in and my wifi works great.

Mikentosh80