I thought I'd outline the steps it took to move a Linksys WRT610N r2 with original Linksys/Cisco software to one running the latest (as of this date) Toastman Tomato software, so that others could find the steps involved in one location. Comments and suggestions are welcome:
1. Check out http://tomatousb.org/doc:build-types and http://tomatousb.org/doc:build-features-cross-reference to get an idea of what features you might want in the new software. Note that for the WRT601N r2 router you must use the 2.6 kernel and cpu R2 version(s). Download the Toastman build you want from the 4Shared site (http://www.4shared.com/dir/v1BuINP3/Toastman_Builds.htm#dir=79224825 ).
2. Make sure you have written down ALL of your current pertinent settings of the router.
3. Download dd-wrt.v24-14896_NEWD-2_K2.6_mini_wrt610nv2.bin from the DD-WRT site. (You use dd-wrt to upload the Tomato version you want to use - you must use a version that has K2.6_mini_wrt610_nv2 in the name).
4. Set your computer address to 192.168.1.101 (example) and the gateway address to 192.168.1.1, as the current Toastman builds do not enable DHCP by default.
5. Do a 30/30/30 reset (see http://www.dd-wrt.com/wiki/index.php/30/30/30_method )
6. Use the current Linksys firmware to upload the dd-wrt firmware by navigating to the Administration section and find the tab regarding firmware updates.
7. Wait five minutes—the router should reboot and come back up with the new DD-WRT firmware installed.
8. Do another 30/30/30 reset.
9. After the router finishes this reboot, navigate to 192.168.1.1. You may see a page come up that prompts you to change information for security purposes. (I had not seen this mentioned in any of the other steps I've seen in other posts.) I put in the router id of dd-wrt and changed the pasword. The page then refreshes and shows a status page.
10. Navigate to the Administration section and find the section that allows uploading firmware updates.
11. Prepare to upload the Toastman Tomato build by renaming the Toastman build from a file extension of .trx to .BIN
12. Use the newly installed dd-wrt to upload the Toastman Tomato build that now has the .BIN extension.
13. Wait five minutes while the software installs and reboots the router.
14. Do another 30/30/30 reset.
15. Login by using the user id of admin, password admin and start setting things back up.
16. Enjoy the features that the Tomato software offers!