What exactly are you looking for in it? I'm not sure whether you can get web only organisers that operate on a long range like mobiles... if they did, they'd be based on mobile technology.
I use my iPod touch (£180) as an organiser. You can make post-it type notes on it (which unfortunately you can't seem to export to PC), but it's great for contacts, email and calendar.
Contacts: you can add contacts and edit many fields including email, web and address. Tapping on either of those can niftily start up a different application, e.g. send an email, visit homepage or show their location on Google maps (requires wireless internet connection for email, web and Google maps). Contacts are synchable with Microsoft Outlook, so you'll always stay up to date both on the touch and on your PC.
Calender: also synchable with Outlook, so appointments and notes will always be up to date. You can add/delete appointments on the touch and synch them back to Outlook.
Email and internet: as mentioned, requires wireless connection in home, workplace or building (you can connect it to any connection it picks up, depending on range, unencrypted or whether you know the password).
