Update: 10/21/07: SERO Update: I've been informed that the address "savings@sprintemi.com" still works for new SERO sign-ups. It is unclear to me if Sprint intentionally left this address available, and if so, for whom. Since the older addresses now yield a "promotion ended" type message, use this with some caution. In other words, I do not know if Sprint could later say they did not intend for this method to be available to the public. Anyway, this is a generic problem with the proliferation of essentially undocumented plans. Each of the carriers have some undocumented plans for special circumstances, but it can be difficult for us to know who they are supposed to apply to. See "SERO" section below for more information.

9/30/2007 Push to Talk "v2.0": As I understand it, Sprint is hoping to dramatically improve call setup times with EVDO rev A and licensed software from Qualcomm called Qchat. Sort of a CDMA push to talk v2.0 (after the essentially failed ready-link attempt). We do see evidence of a widepread upgrades to EVDO rev A. The press I've read indicates call setup time has been reduced to 1 second, and is interoperable with existing Nextel customers. If this works well enough, it could be a saving grace for Sprint who has struggled to integrate the technologies from acquired Nextel (with their existing CDMA customer base). Here's an older article announcing this, which includes the explaination. Here in Oregon, it would appear that Sprint's entire native non-affiliate network has been upgraded to EVDO rev A. We'll be able to know if this all "really works" soon enough. Note that ready-link "really worked," but the common customer complaint was that it took too long to establish communication. Nextel's IDEN based push to talk is essentially immediate (with virtually no call setup time). Even if you don't use push to talk, it's great to have the faster EVDO rev A speed for data, and to know that Sprint has motivation to overlay revision A virtually everywhere they provide service (to avoid coverage map discrepencies).

Sprint and Nextel Merger: We are finally seeing widespread integration of tower resources between the two companies. The new sites are called synergy sites and they definitely are boosting Sprint's coverage.

Sprint "firing" some customers: There has been some widespread press that Sprint has selected specific customers for cancellation when they call customer service too much (presumably searching for deals), and for folks who roam too much.

Customer Service: Sprint continues to struggle with providing decent customer service. I do think plans are under way to help improve this, which may involve reducing the perks folks sometimes get by calling in repeatedly. Hopefully, they will get decent customer service out of this process.

My Take: If you pay for this stuff yourself, and need a PDA phone with data, no one can touch the SERO offering which currently includes unlimited data from the handset.

SERO- This special "SERO" deal is not currently being offered to the public. You may still qualify for this plan if you actually know a Sprint employee. Anyway, there is no guarentee this deal will return.
SERO: This is a special rate plan that can only be seen on the web. It has been a really excellent deal, however, since it's basically an unadvertised plan theoretically for friends of employees its terms can change without notice. This deal seems like a match made in heaven for former AT&T TDMA customers who have been essentially given the boot-- assuming Sprint works in your area. If you don't mind the extra leg work, you can call them and see what it currently provides and see if it is a good match for you. The web page will display a phone number that can be called for information and ordering. The basic plan for $30 includes 500 peak minutes, unlimited off-peak starting at 7pm including weekends. They key though is that this plan has been including unlimited data from the handset, including for PDA phones. It has historically included roaming (no more than 800 minutes or 50% of total usage per month). SERO subscribers in June, got all of this plus unlimited SMS text messaging (which does not appear to be available now). To see the plans, go to http://sprint.com/sero. Login with email address "savings@sprint.com"
SERO Warning: Despite the fact that this is literally the best deal I have ever seen in post-paid cellular plans, I have to say that this is not an advertised plan. This means that customer service may not know what you are talking about when you call. Given that it is not advertised, the terms of this plan can change very rapidly and without notice. For this reason, call and verify the features you expect and require before ordering. As of 7/14/2007 the correct phone number to call is 1-888-882-4030.
Notes: Provided you get the terms you expect when you sign up, those will not change during your two year contract (and may never change unless you request a rate-plan change). So while this offer does change over time, they don't change the terms on you after you sign up.
Update 7/20/07 - "Sero" closed to general public. The "savings@sprint.com" no longer works...