Switching from Canon to Nikon?

I currently have a nameless Canon T_i, and a Sigma 18-200mm, a 50 f/1.8. I'm considering for my next camera upgrading to a Nikon D300. What would be the easiest/most economical way of switching to Nikon?
Thanks!

Added (1). Are there any websites great for Selling Equiptment?

Canon parts (lenses, batteries, etc.) are not interchangeable with Nikon. Unless you have the money to buy all the Nikon parts, your best bet would be to sell your Canon stuff first. Then again, you'll be temporarily without a camera if you do that.

EBay, or trade your equipment in at a camera store. Some on-line camera stores will allow you to trade in your old stuff, but check their reputation first as you usually have to send your equipment in first, before you get an estimate on how much they will give you.

If you use eBay, you can search on recently completed auctions for your equipment to see what the going rate is.

I've purchased NIKON lenses from Ebay with good results. So I'd say sell yours on EBAY, but be very clear about the true condition of what you are selling so you have a very happy customer. On Ebay you are likely to get the most money selling.

There are camera stores that sell on line, Adorama http://www.adorama.com/...orama.com/ is one I use and have been to their NY store in person. I've also been to B & H http://www.bhphotovideo.com/...video.com/ cameras in NYC. They sell used equipment and buy old cameras and lenses from customers. If you can go to a camera store IN PERSON to sell your equipment you have a better chance of negotiating a trade for the new items you want as a package deal. That would be your most economical way of switching.

You may want to contact them via telephone to see what they will do, however they can't examine what you have over the phone so it's likley that your offer will be slightly lower than if you can do it in person, depending on the condition of your equipment.

And quite frankly the busier and larger the store, the better deal you will make. Both of those stores are busy and large. They sell at a discount, and buy at a discount. What should be important to you is what the difference will cost you overall for the package, buy and sell.

I was not so happy with a purchase made from an on-line only camera seller. They made substitutes that I did not authorize and I had no way of getting what I truely paid for from them.

If it's a Canon, it's not nameless. Upgrading is always painful. There's no other way. Sell all your Canon equipment, including the Sigma then start from scratch into Nikon. Websites? Havn't you heard of eBay? I'm not from the US but you should also be familiar with Craigslist.com.

YOURE MAKING A MISTAKE! DON't SWITCH TO NIKON!