well how clever is this? hehehehe.. wonderful idea

I agree Ernest..
cool idea!!..

its a great idea and to make it even stand out more I suggest you add some shadows below some parts of the edges of the stamp because stamps tend to get loose on the edges a bit the cutout could have been done a lil bit better or choose a different method of cutting off the edge. perhaps if u place a row of small circles next to eachother on the same height with a lil space between them and then used those to cut the edge of the stamp, that you can make that stamp edge cutout more realistic and less like it has been cut with one of those craft scissors with the swirly zigzag blades etc.. also you did a very nice work on the inkstamp on the stamp

the postmark stamp looks great! i think the actual stamp could use some work. The flowers and the stamp feel like two different color pallets are used. If you use the "Match Color" adjustment it will help shift the colors to match better (Image > Adjustments > Match Color). Just have the layer selected that the color needs to be adjusted, then in the match color, select the source, being the layer that you want to match the color to. adjust the sliders until you get the look that you want and you are good. ;] Great work overall! good luck!