With dot-com fever continuing to rise in Silicon Alley, some of the city’s oldest, largest and most conservative law firms have decided that they, too, want to be players in the new economy, even if it means rethinking the way they do business.

In an accommodation to cash-poor start-ups, some firms are now allowing clients to pay at least a portion of their fee in stock. Other firms have begun to establish investment funds, through which partners, and sometimes even associates, invest directly in their high-tech clients.