Rivka,
First of all, welcome to RCT*Mart! We're glad you found the site and like what we have here.
Secondly, we strongly encourage our members to post their own creations. We have a special section set up just for that. Head on over to
The Stock Room and find the appropriate sub-forum for whatever it is you'd like to share with us.
Members are given a limited allowance of upload space to use, so if you have off-site hosting space (either freewebs, or AOL, etc.) you can link directly to the downloads there. Otherwise you may upload an attachment to your post/topic (be sure to use .zip for any parks or track tiles - it will save you some space).
Have fun, and let us know if you have any other questions!!