What is the easiest way to restrict content to a certain group?

[kobescoresagain]

I have content that I am intergrating into a couple pages right now, everything seems to be working right, but I want to know how I can keep certain people from seeing it. I want to know basically something like and if statement that would do something liek this

if (usergroup == admin)
{
Show
}
else
{
Show something else
}