Generally, this is not taxable income. Suppose you bought your property for $100,000 and you sold the strip for $10,000. You would report this as a capital transaction on schedule D under sales of stocks and investments (choose the category of "other property", not "your house." You would report that you bought the land for $10,000 on the date you bought it, and that you sold it for $10,000 on the date you sold it. Since there is no gain, no tax is owed. However, selling the strip of land reduces your cost basis on the rest of the property--whenever your sell the rest of the property, you would report your purchase price or adjusted cost basis to be $90,000 (your cost basis is reduced by the amount of payment for the strip of land).
In the event the payment was more than your original cost for the entire property, reporting it as I described will create a taxable gain, and the adjusted basis of your property going forward will be zero.
