I created a whole series of posts covering social media buttons for a range of apps such as twitter, delicious, designfloat, google, stumbleupon and digg and its being released now (it may even be finished by the time you get you read this) so if your looking for some icons, badges or buttons all in one place, have a browse over the social media buttons, badges and icons post.
It was only recently I was searching for exactly this type of button to add to my blog and as luck would have it this fine selection came along. I hope they come in useful for you.
If you read my twitter post yesterday then you may have taken the time to signup and get onboard with twitter. If you have and you want more then you need to check out this post by