It can be quite difficult adding Instagram filters to your pictures if you don't have an iPhone and if you're not so good with Photoshop. With PicYou you can add Instagram filters to your pictures quickly and easily. PicYou is a social picture sharing site like Instagram however anyone can use it. You can like pictures, follow people and others can follow you just like Instagram.
Uploading and adding filters is very easy and from there you can post them to Twitter or Facebook.
It may not be as big as Instagram but it's a start.